Title of Invention	MAGNESIUM-BASED PRIMARY (NON-RECHARGEABLE) AND SECONDARY (RECHARGEABLE) BATTERIES
Abstract	The batteries described herein are of the type comprising at least one anode, at least one anode, at least one cathode and at least one electrolyte, and current collectors, in which at least the anode is magnesium-based, and optionally also the cathode and the electrolyte contain magnesium. Assembly of the batteries involves the preparation of the individual components and the interposition of a thin layer of electrolyte between the magnesium-based anode and the cathode.

Title of Invention

MAGNESIUM-BASED PRIMARY (NON-RECHARGEABLE) AND SECONDARY (RECHARGEABLE) BATTERIES

Abstract

The batteries described herein are of the type comprising at least one anode, at least one anode, at least one cathode and at least one electrolyte, and current collectors, in which at least the anode is magnesium-based, and optionally also the cathode and the electrolyte contain magnesium. Assembly of the batteries involves the preparation of the individual components and the interposition of a thin layer of electrolyte between the magnesium-based anode and the cathode.

Full Text	Scope of the invention The present invention regards primary (i.e., non-rechargeable) and secondary (i.e., rechargeable) batteries in which at least the anode contains magnesium, and optionally also the electrolyte and cathode contain magnesium, as well as methods for making said batteries. Prior art As is known, the enormous and rapid development of digital electronics that has taken place in recent years has enabled the creation of a large number of new portable devices, such as computers, cellphones, videocameras, etc. These devices are almost exclusively equipped with storage batteries built according to a single technology; namely nickel-cadmium (Ni-Cd) batteries. The need to produce ever smaller and lighter portable devices, together with the need for long operating autonomy of these devices, has pushed numerous private firms operating in the sector, as well as public research bodies, to cany out research aimed at developing new technologies capable of meeting the requirements referred to above. In the late eighties and early nineties, two new types of batteries appeared on the market: nickel-metal hydride (Ni-MH) and lithium-ion (Li-ion) batteries. In just a few years, the performance of batteries produced using these technologies has improved considerably, to the extent that today the performance of these batteries is superior to that of nickel-cadmium batteries. A further advantage of the batteries produced using these new technologies is the absence of cadmium, which, since it is a heavy metal, has quite a serious detrimental impact on the environment. As is known, lithium-ion batteries are, in energy terms, still the most promising ones, but their production cost is relatively high. However, if the cost per cycle of these systems is considered, it may be noted that they become competitive as compared to the more economical nickel-cadmium batteries. On the basis of the technical characteristics, environmental impact, and cost per cycle, a considerable growth is expected for the lithium-ion system on the world market. On the other hand, nickel-metal hydride batteries are likely to have a more modest growth, whilst it is estimated that nickel-cadmium batteries are unlikely to maintain their current production levels. The international scenario witnesses a concentration of the majority of production in the sector of lithium-ion batteries, which are an evolution of lithium systems. Primary lithium batteries, which are widely used in calculators, clocks and watches, cardiac pacemakers, etc., are made with a lithium anode and a cathode made of transition metal oxide (e.g., Mn02). Thanks to the high electrochemical potential supplied by the lithium anode, these batteries provide high cell voltages, and consequently also high energy densities. However, these systems are not reversible, or at the most are usable for just a few cycles. The idea of exploiting lithium to make secondary batteries has given rise to a first technology known as lithium-polymer (Li-polymer) technology. This method, which exploits metallic lithium for making the anode, presents, however, serious difficulties in terms of reversibility. In fact, during the recharging phase, dendritic deposits are formed on the surface of the anode, which are the result of the reaction of the lithium with the organic polymeric electrolyte and are responsible for the fast deterioration of this type of battery. At best, the number of cycles obtained using systems of this type thus amounts to just a few dozens or hundreds. On the other hand, the reactivity of the lithium in regard to the polymeric electrolyte may also become a cause of serious problems of safety in the operating phase of the battery itself. The next step in the development of these devices was that of the introduction of the so-called lithium-ion or rocking-chair technology, which is based on solutions that tend to solve the problem of formation of dendrites on the lithium anode by replacing the lithium with composite materials capable of intercalating Li* in their structure via insertion reactions. In recent years, it has been possible to produce anodes based on carbon with properties of intercalation. Certain carbons with a regular structure (turbostatic or graphitizabie) or with a highly crystalline structure (natural or synthetic graphites) can in fact intercalate the Li4 ion in their layers in a reversible manner, thus giving rise to complexes of the LixC6 type. Other lithium-ion batteries are provided with an intercalated titanium disulphide- based (LixTiS2) anode. The latter has a behaviour similar to that of a carbon electrode. Usually the cathode is instead made using oxides of lithium and transition metals, among which the most widely used up to now is lithium cobaltate (UC0O2), which, for reasons of cost, availability, and toxicity, tends to be replaced by lithium nickelate (LiNi02) or lithium manganate (LiMn04). The number of cycles achievable using the rocking-chair technology reaches one thousand. Usually, in these systems the electrolyte consists of an organic polymer with solvent properties, which is rendered ionic-conductive by being doped with special lithium salts (e.g., LiPF6f LiCI04f etc.). Notwithstanding the fact that the above-mentioned technological advances tend to solve the problems linked to the use of lithium on account of the high reactivity of this element, and in particular the main problem linked to the formation of dendrites on the anode, research for a complete solution to these problems is still very much in progress. The problem of the formation of dendrites has not yet been completely solved, whilst likewise the problem of high reactivity of lithium, together with the known problems of safety referred to previously, and the problem of reversibility still remain open. Magnesium could be an element usable for overcoming these problems, and in particular as a replacement for lithium. As reported in the literature, a number of researchers, such as Farrington and Cherng have sought to develop magnesium-based polymeric electrolyte systems for the possible development of magnesium batteries, with, however, somewhat meagre results. The polymeric electrolytes obtained had, in fact, conductivities which, at room temperature, were too high (i.e., with conductivity lower than 10"6 siemens/cm) for the production of primary and/or secondary batteries. Nevertheless, in the patent US44575 Moulton suggests the possibility of making magnesium batteries, without, however, specifying the procedure, in particular without specifying how to make the anode, cathode and polymeric electrolyte. Polymeric electrolytes doped with magnesium salts are cited, which, when tested, yielded resistivities higher than 107 ohm.cm at room temperature, whereas in order to be able to make the batteries it.is necessary for the resistivity values to drop below than 105 ohmcm. The main task of the present invention is to succeed in developing primary (non-rechargeable) batteries and/or secondary (rechargeable) batteries that overcome the problems of reactivity and reversibility typical of lithium-based batteries. In the framework of the above-mentioned task, a consequent primary purpose is to develop batteries with high-level technical characteristics allied to a reduction in production costs. Another important purpose is to develop miniaturized and lightweight batteries. Yet a further purpose is to develop batteries suitable for use in portable digital electronic equipment. A further important purpose is to arrive at the almost total elimination of environmental impact. Summary of the invention These and other purposes, which will appear more clearly in what follows, are achieved by primary (non-rechargeable) and secondary (rechargeable) batteries that form the object of the present invention, of the type comprising at least one anode, at least one cathode, at least one electrolyte, and current collectors, said batteries being characterized in that at least the anode and preferentially ajso the electrolyte contain magnesium. Also the cathode of the batteries that form the object of the present invention may optionally incorporate magnesium. The anode included in the present invention is characterized in that it uses magnesium in the various states of oxidation Mgn+(0~n£2), optionally combined with metallic magnesium, and the electrolyte, possibly containing- magnesium, is characterized in that it comprises any ionic species of magnesium in solvents, including polymeric solvents, that are capable of producing electrolytes having good ionic conductivity and capable of solvation of the said ionic species. i/Vhen the cathode contains magnesium, this is a species of magnesium in the state of oxidation 2+ and may have a substrate of highly conductive inorganic or organic materials, or else may be intercalated or embedded in highly conductive inorganic or organic materials. Forming a further object of the present invention are methods for the production of said primary and secondary batteries of the type comprising at least one anode, at least one cathode, at least one electrolyte set between anode and cathode, and electrical-connection collectors, said batteries being characterized in that at least the anode and the electrolyte contain magnesium and even the cathode can optionally contain magnesium. Brief description of the figure Figure 1 is a schematic sectional view of a battery built according to the present invention, where: 10 designates an anode which has the characteristics and is made as is described in detail in what follows; 11 designates a cathode which has the characteristics and is made as is described in detail in what follows; 12 designates an electrolyte which has the characteristics and is made as is described in detail in what follows and 13 designates current collectors which have the characteristics and are made as is described in detail in what follows:- Detailed description of the invention Notwithstanding the fact that the attempts referred to above failed to lead to promising results, the present inventors have now surprisingly found that magnesium is an element that can be usefully employed in making primary and secondary batteries. Following on extensive and ample research, the present inventors have in fact found that, for the purposes of the present invention, i.e., for obtaining primary and secondary batteries with technical performance comparable, if not superior, to that of lithium batteries at present in use or known, reference being made to the — aforementioned Figure, the batteries that form the object of the present invention may be primary and secondary batteries of the type comprising at least one anode, at least one cathode, at least one electrolyte set between anode and cathode, and current collectors, said batteries being characterized in that at least the anode and preferentially also the electrolyte contain magnesium. ' In the batteries that form the object of the present invention also the cathode may optionally incorporate magnesium. When the cathode does not contain magnesium, it is a conventional cathode, and hence is in itself known, and consequently will not be described further herein. The primary and secondary batteries that form the object of the present invention may moreover comprise possible dielectric spacers, not illustrated in the Figure. In particular, the batteries according to the present invention may be made up of: An anode 10 characterized in that it comprises magnesium in the various states of oxidation Mgn+{0n2,f optionally combined with metallic magnesium. In said anode, the magnesium may be included as such or may also have a substrate of highly conductive inorganic or organic materials, or else of highly conductive inorganic or organic materials that are capable of englobing, by intercalation or embedding into their own matrices, magnesium crystallites of reduced dimensions or magnesium monocrystals. In particular, the anode 10 may consist of metallic magnesium as such, and in this case the magnesiurrrmay be used in laminated or sintered form. In the case, instead, where the magnesium has a substrate of highly conductive materials, these may be inorganic materials chosen from the group made up of metals, for example aluminium, copper, and other equivalent metals, or oxides, alloys, and fabrics made of the same. The said highly conductive substrate materials may also be organic, and also of a polymeric type; in the latter case, they are chosen from among materials such as carbon-fibre fabrics, graphite, or even graphite-based composite materials, or other equivalent materials suitable for the purposes. Also in the case where intercalation or embedding materials are used for the .anode, this may be either organic or inorganic. The intercalation or embedding materials that may be used for the purposes of the present invention are transition-metal compounds, alkaline-metal compounds, and alkaline earth-metal compounds, as well as non-metal compounds, chosen from among oxides, sulphides, phosphates or phosphides, such as tungsten oxides (WyOx), ferric oxides (FeyOx), titanium sulphides (TiySx), cobalt oxides (CoyOx), nickel oxides (NiyOx), manganese oxide (MnyOx), or else other equivalent compounds, or carbon-based materials with intercalation properties and with a highly crystalline structure or an irregular structure, or equivalent materials, or else a material of a polymeric type, such as carbon-based polymers or equivalent polymers that are capable of englGbjngl_b_y_jotercaIation.jDr_embedding. into._their_.own. matrices, magnesium crystallites of reduced dimensions or magnesium monocrystals. Furthermore said anode 10 may be optionally oxidized with oxidizing agents such as oxygen gas or peroxide, such as H2O2, or organic peroxides and stabilized by treatment with stabilizing agents such as alkoxides, (e.g. tetra-alkoxy titanium, tetra-alkoxy silanes, trialkoxy aluminium, tetra-alkoxy zirconium, or magnesium dialkoxide, or equivalent compounds). A cathode 11 characterized in that it contains magnesium species with state of oxidation 2. In the case where the cathode contains magnesium, the latter may have a substrate of highly conductive inorganic or organic materials, including polymeric materials, or else the magnesium may be intercalated or embedded in inorganic or organic materials. The materials that may be used both in the case where the magnesium has a substrate and in the case where the magnesium is intercalated or embedded are the same as the materials mentioned previously for the anode. This type of cathode may be used, dispersing the active material in a porous and conductive matrix. This use affords the advantage of improving the electrochemical properties of the batteries. Also the cathode may be optionally oxidized with the same oxidizing agents. The oxidation of the cathode may be, like the anode, in situ and following on its preparation or, unlike the anode, the cathode may be prepared with electrochemically active materials that have been partially oxidized prior to its preparation. When the cathode 11 does not contain magnesium, it is a conventional cathode and is in itself known; consequently, it is not further described herein. In this case, anyway, the cathode contains electrochemically active materials having a base of metallic mixtures in appropriate proportions in a reduced or oxidized form. For this purpose, as is known from the prior art, materials containing transition metals may be used, such as, but not exclusively, manganese with state of oxidation ranging from 7* to 2+, and other equivalent metals. An electrolyte 12 characterized in that it comprises any ionic species of magnesium in solvents, including polymeric solvents, capable of producing electrolytes with good ionic conductivity and capable of solvating said species. The electrolyte according to the present invention comprises, as tonic species of magnesium, magnesium salts or complexes of the general formula Mg(R)yX2-y, with 0 The radical R may be chosen from the group consisting, for example, of alkyls with C1-C7 chains, whilst X may be chosen from among halides, CI04, (CF3)ixS03-x, with 0 The solvents used for the^ electrolyte may be of various types, since the essential characteristic required is that they should possess good ionic conductivity and in any case that they should at the same time be able to solvate the magnesium salts or magnesium complexes that have been chosen. For the purpose, they may therefore be liquid solvents or solvents in the solid or viscous state. In the case of liquid solvents, these are chosen from among materials having polar groups which are able to co-ordinate and dissociate the ionic magnesium salts or complexes and which contain oxygen, nitrogen, sulphur and carbon. These solvents may therefore be chosen from among ethers, alcohols, di-alcohols, esters, amines and amides, thioethers, thioalcohols, thioesters, alkyl carbonates and alkyl thiocarbonates, or other equivalents. In the case where the solvent for the electrolyte is solid or viscous, it may be of a polymeric type. Jsable for the purpose are all the polymers or copolymers of the same having jifferent molecular weights, which are capable of solvating magnesium salts or :omplexes suitable for the purpose. Such polymers and/or copolymers may be chosen from among polyaikylene oxides, polyalkylene glycols, polycarbonates, polyalkyl siloxanes, polyethylene diaminotetra-acetate, or equivalent polymers or copolymers of the same macromolecular frameworks having different molecular weights, also containing, in their chains, hetero-atoms of the oxygen, nitrogen, silicon, and phosphorus types. Also usable for the purpose are polyphosphazene polymers functionalized with the polymers and/or copolymers mentioned previously. To provide examples, among polyalkylene oxides, the following may be mentioned: polymethylene oxide, polyethylene oxide, polypropylene oxide and others; among polyalkylene glycols, the following may be mentioned: polymethylene glycols, polyethylene glycols, polypropylene glycols and fluorinated derivatives of the same and others; among polycarbonates, the following may be mentioned: polymethylene carbonates, polyethylene carbonates, and polypropylene carbonates and others; among the polyalkyl siloxanes, the following may be mentioned: polymethyl siloxane, polyethyl siloxane, and polypropyl siloxane and others. Also usable for the purpose are copolymers derived from the polyalkylene oxides and polyalkylene glycols, polycarbonates, polyalkyl siloxanes, polyethylene diaminotetra-acetate; polyalkylene glycols and polycarbonates, polyalkyl siloxanes, polyethylene diaminotetra-acetate; polycarbonates and polyalkyl siloxanes, polyethylene diaminotetra-acetate; polyalkyl siloxanes and polyethylene diaminotetra-acetate such as, as example, polyethylene oxide-polypropylene oxide, polymethylene oxide-polyethylene oxide, and polymethylene oxide-polypropylene oxide; polyethylene oxide-polymethylene carbonate, polypropylene oxide-polyethylene carbonate, and polyethylene oxide- polypropylene carbonate; polyethylene glycol- polymethyl polysiloxane, polyethylene oxide-polymethyl siloxane, and polyethylene oxide- polyethylene diaminotetra-acetate, etc. It is also possible to use for the purpose, for instance, polyphosfihazene polymers functionalized with polymers and/or copolymers of the polyethylene-oxide type or the like having different molecular weights. The polymers and/or copolymers that may be used for the preparation of the electrolyte may moreover be functionalized with groups that bond or co-ordinate magnesium so as to improve their interaction with the salts or complexes of the latter. For the purpose of improving the ionic conductivity of the electrolyte, this may also be optionally acidified or alkaiinized according to known procedures, which, consequently, will not be described in greater detail herein. In the case where the electrolyte is acidified, however, the preferential acidifying agents for the electrolyte are compounds with a base of phosphorus, polyphosphates, P2O5, or equivalents of the orthophosphoric-acid type. In the case where the electrolyte is alkaiinized, the compounds that may be used are nitrogen-based ones and, in this case, are preferentially amines or ammonia, as well as basic derivatives of sulphur and phosphorus. Acidification improves the conductivity of the electrolyte, and this process is to be carried out whenever the performance of the electrolyte is not adequate for the application. This process is to be preferred in the case of stabilized electrodes. Also alkalinization improves the conductivity of the electrolyte and is carried out with the purpose of favouring the electrochemical functioning of the electrodes. This process is, however, to be preferred in the case where non-stabilized electrodes are used. Spacers (not shown in the Figure) consisting of inorganic or organic materials which are permeable to ions and have high dielectric characteristics; these are appropriately functionalized, if necessary, in order to eliminate the polar groups that may be present on the surfaces of the fibres. For the purpose it is possible to use, for example, cellulose, glass-fibre fabrics, organic membranes, or other equivalent materials. Current collectors 13, either metallic or non-metallic, with conductive characteristics and with a resistivity of not more than 10 ohm»m for collecting the electrons and for electrical connection of the poles of the battery element. For the purpose, it is possible, for example, to use metals, even in the form of oxides, alloys, and fabrics made of the same, such as aluminium, copper, steel, brass, etc., or organic materials made of carbon or carbon-fibre fabrics, or similar materials. The method for making the primary and/or secondary batteries according to the present invention envisages at least one of the following steps: - preparation of an anode characterized in that it comprises magnesium in the various states of oxidation Mgn+ ((Kn2), optionally combined with metallic Mg, said anode having a base of metallic magnesium as such, or else of magnesium on a substrate of highly conductive inorganic or organic materials, or in inorganic or organic materials for intercalation or embedding of the magnesium; - preparation of a cathode characterized in that it comprises species of magnesium in the state of oxidation 2* having a substrate of highly conductive inorganic or organic materials or in inorganic or organic composite materials for intercalation or embedding of the magnesium; - preparation of an electrolyte characterized in that it comprises any ionic species of magnesium in solvents that are capable of producing electrolytes having good ionic conductivity and of solvating said species. The electrolyte may moreover optionally be reinforced with spacers as described previously. The above three components are put in contact with one another, the layer of electrolyte 12 being set irLbetween the anode 10 and the cathode 11. The intimate contact between anode 10, electrolyte 12, and cathode 11 may also be obtained by exerting a slight pressure on the ensemble of components at temperatures of between room temperature and approximately 150°C. To obtain batteries with adequate performance, the same technologies may be adopted as those used for the preparation of the already known lithium batteries. In particular, it is possible to: - use single-layer or multi-layer button battery technology; - connect the multi-layer films in parallel (parallel stacking), or else connect the multMayer films in series (bipolar stacking), for non-folded structures; - use flat-roll design technology or jelly-roll design technology, or flat-stack design technology for folded structures. Described in detail in what follows are the methodologies for the preparation of the individual components when these contain magnesium, and hence are not conventional and so known, both in terms of characteristics and in terms of production methodologies, to any person skilled in the branch. A - General methodologies for the preparation of the components A. 1 - Preparation of the anode 10 For the purposes of the present invention, three types of anode 10 may be used: a magnesium-based anode having the characteristics already mentioned previously, (i) as such or (ii) on a substrate of highly conductive organic or inorganic materials, or (iii) intercalated or embedded in material for intercalation or embedding of magnesium. The magnesium as such may be laminated starting from Grignard-grade magnesium, or may be in the form of powder of appropriate grain size, or else in the form of a ribbon of varying length, which is commercially available. In addition, the magnesium may also be sintered. The anode may also consist of magnesium on a substrate of highly conductive organic or inorganic materials, including polymeric materials, as described previously. This type of anode may be prepared by chemical, thermal vapour, electrolytic, or electrochemical deposition methods of magnesium species. The other type of anode 10 is made with intercalation or embedding material for magnesium. Particularly this anode is prepared by suspending, in a solvent such as benzene, toluene, N-N dimethyl acetamide, dimethyl formamide, or tetrahydrofuran or the like, a mixture of polyethylene or polyvinyl chloride, or polyacrylamide, or polyacrylonitrile, or some other, with intercalation material previously extended up to complete homogenization with magnesium. The system is treated until complete and homogeneous distribution of the above described materials in the solvent itself is obtained. The composite film with a base of intercalation or embedding material is then obtained by slow evaporation of the solvent. Other methods of intercalation, in addition to the ones described previously, for obtaining the anode, may be based on physical methodologies, such as plasma spraying or sputtering of the magnesium into the intercalation or embedding material chosen. Whatever the type of anode, this may possibly be subsequently oxidized with oxygen gas or peroxide, such as H2O2, or organic peroxides. The anode may, moreover, be subjected to a further and possible stabilization treatment. As stabilizing agents may be used alkoxides, such as tetra-alkoxy titanium, tetra-alkoxy silanes, trialkoxy aluminium, tetra-alkoxy zirconium, or magnesium dialkoxide, or other equivalent compounds. With the above further processes it is possible to obtain an anode that presents better characteristics of stability, reversibility, and exchange currents. A.2 - Preparation of the cathode 11 The cathode 11 may be prepared either providing a substrate for the magnesium or with a composite having a base of intercalation or embedding material, adopting methodologies that are similar to the ones already described for the anode 10, and which, for this reason, will not be described further herein. The intercalation materials are the same as those usable for the anode and may be, for example, but not exclusively, with a base of carbon, graphite, titanium disulphide (TiS2), cobalt dioxide (Co02), nickel dioxide (NiC^). manganese dioxide (MnOa), or other equivalents chosen from among the ones already mentioned previously. Like the anode, also the cathode may undergo further processes of oxidation in situ and following on its preparation, these processes having already been described previously. Unlike the anode, however, the cathode may be prepared with electrochemically active materials that have been partially oxidized prior to the preparation of the cathode. A.3 - Preparation of the intercalation material The intercalation material is chosen from among the materials that may be used for this purpose in the anode or in the cathode, and is prepared according to the general procedure described in what follows. The intercalation material is ground in a ball mill until complete structural disorder of the material is achieved. Subsequently, the material is brought into intimate contact with magnesium carbonates or magnesium oxides. The mixture thus obtained, after homogenization and peptization is brought up to a temperature of approximately 100°C to 400°C for a period of between 1 and 3 hours, and subsequently to a temperature of between 800°C and 1200°C under a inert atmosphere (for example, an argon atmosphere), and then kept at the temperature range indicated in vacuum conditions for 1 to 5 days. A.4 - Preparation of the electrolyte 12 The electrolyte 12 according to the present invention may be prepared using solvents, including, but not exclusively, polymeric solvents, capable of solvating any ionic species of magnesium and of producing electrolytes having good ionic conductivity. The electrolyte according to the present invention comprises, as ionic species, magnesium salts or magnesium complexes of the general formula Mg(R)yX2-y, with 0 electrolyte The mode of preparation of the electrolyte 12 according to the above reaction can follow three general procedures. The first regards the direct dissolution of the magnesium salt or complex in the liquid solvent or in the melted polymer (when the latter so permits). The second procedure regards the dissolution of the polymer solvent and the magnesium salt or complex in a common solvent to obtain the polymeric film through slow evaporation of the solvent (solvent-casting). The third procedure regards obtaining polymeric electrolytes which can have a high conductivity and which are based on polymeric electrolytes having a high degree of crosslinking. In these circumstances, the polymeric electrolyte, for obvious reasons, must be prepared obtaining solutions of the monomer and of the magnesium salt or complex preliminarily, and carrying out the polymerization reaction subsequently. The solvents usable for the purpose are a\\ those already mentioned previously, and in particular, to provide an example, any liquid material having polar groups containing oxygen, nitrogen, sulphur, and carbon, which co-ordinate and dissociate the ionic magnesium salts or complexes, such as ethers, alcohols, di-alcohols, esters, amines and amides, thioethers, thioalcohols, thioesters, alkyl carbonates and alkyl thiocarbonates, or else polymers and/or copolymers with different molecular weights, polyalkylene oxides, polyalkylene glycols, polycarbonates, polyalkyl siloxanes, polyethylene diaminotetra-acetate, derivatives thereof in which one or more atoms in the chain are substituted with one or more hetero-atoms chosen from among oxygen, nitrogen, silicon, and phosphorus and polyphosphazene polymers functionalized with the polymers or copolymers mentioned previously. Among the magnesium salts or complexes that may be used for the purposes of the present invention, particularly advantageous is 5-MgCI2, which, since It has a very low lattice energy, i.e., close to 0 kcal/moL, may be solubilized in organic solvents that are capable of co-ordinating the magnesium, and Grignard magnesium as species generating cations for the electrolyte. The electrolyte obtained according to one of the processes described above may also be acidified or alkalinized with the use of procedures and means known for the purpose. In the case where the electrolyte is acidified, it may be preferential for the purposes of the present invention to add appropriate amounts of phosphorus-based compounds, such as P2O5, or other equivalents, under stirring and up to complete dissolution. A^similar procedure is followed in the case where the electrolyte is alkalinized with nitrogen-based compounds or with basic derivatives of sulphur and phosphorus. A.5 - Preparation of the dielectric spacers The dielectric spacers may be made of any ion-permeable insulating materials having good characteristics of insulating strength and dielectric constant. In the case where the material has polar groups on its surface, chemical inertization is performed by means of appropriate functionalization to prevent interaction with the magnesium ions or with ionic complexes of magnesium. In the case of glass fibres, for example, the hydroxyl groups present on the surface are de-activated by reaction with triethoxyalkyl silane, thus rendering the surface of the spacer highly apolar. B - General examples for the production of the components The invention is hereinafter further clarified in its general aspects and through a few examples of practical implementation, which have the sole purpose of illustrating the invention without limiting the scope thereof in any way, B.1 - Example of preparation of the anode 10 by sintering The anode 10 is prepared starting from metallic magnesium which is finely ground and sintered applying a pressure of 1400 MPa. In this way, after applying the pressure for approximately 10 minutes, a metallic film is obtained having the desired thickness. B.2- Preparation of graphite thermally pre-intercalated with magnesium A mixture of magnesium oxide and graphite, in a weight ratio ca of 3% is rendered disordered using a ball mill. This mechanical mixing proceeds for approximately thirty minutes and has the purpose of intimately homogenizing the two components. The mechanical action of the mill moreover increases the crystallographic disorder of the graphite. The material thus obtained is next introduced into a quartz tube and subjected to six nitrogen-vacuum cycles to eliminate any traces of air. Subsequently, the tube is subjected to a vacuum by means of a diffusion pump at a pressure of 10"6 mbar and brought up to a temperature of 700°C, at which it is kept for approximately 14 hours. B.3 - Preparation of the composite cathode 11 The intercalated graphite, referred to in Example B.2, is suspended in a xylene solution containing, dissolved therein, 10 wt% of polyethylene. From the mixture thus obtained the solvent is made to evaporate slowly (solvent-casting method) to obtain a black, slightly gummy film, which is broken up into tiny flakes and subsequently converted into a sintered cathode 11 by application of a pressure of 1400 MPa. BA- Examples of preparation of the polymers for the electrolyte Example B.4.1 Commercially available polyethylene glycols with molecular weights from 200 up to 1000 maybe used. Example B.4.2 For the preparation of the polymer, it is possible to use commercially available polymers, such as polycarbonates, or equivalent ones. Example B.4.3 - (Synthesis of polyethylene glycol-polydimethyl polysiloxane copolymers) An aliquot of approximately 3 grams of dimethyl dichlorosilane is made to react in toluene with 50 mol% of polyethylene glycol 400. The reaction is conducted in nitrogen for approximately 10 hours. A transparent polymer is obtained having a high viscosity. After eliminating the toluene and the residue of dimethyl dichlorosilane in vacuum conditions (10"3 bar) at a temperature of approximately 120°C, a thick liquid polymer is obtained that resembles honey in appearance. The analyses have shown that the material thus synthesized is a copolymer with blocks of polyethylene oxide and polydimethyl siloxane. Example B.4.4 - (Synthesis of the di-anhydride monomer of ethylene-diaminotetra-acetate acid) Approximately 3 grams of ethylene-diaminotetra-acetate acid are made to react in toluene with acetic anhydride in the presence of small amounts of pyridine. After approximately two hours of refluxing, the white precipitate of the anhydride of the ethylene-diaminotetra-acetate acid is first filtered and then washed with toluene in a rigorously inert nitrogen atmosphere. The white solid thus obtained is subsequently vacuum-dried for approximately one day. The analyses have shown that the product is the anhydride of pure ethylene-diaminotetra-acetate acid. Example B.4.5 - (Synthesis of copolymer with blocks of ethylene-diaminotetra-acetate - polyethylene glycol) The anhydride of the ethylene-diaminotetra-acetate acid is made to a react with a 1:1 aliquot of polyethylene glycol having a molecular weight of from 400 to 800. B. 5- Example of preparation of S magnesium chloride One gram of metallic magnesium is introduced into a 250-ml flask in a rigorously inert argon atmosphere. The flask is prepared in an argon dry box with reflux drip and vacuum cocks. Approximately 100 ml of n-chlorobutane are added to the magnesium using the drip. The mixture thus obtained is made to react for approximately 8 hours under argon flow at the boiling temperature of the chlorobutane. After two hours' reaction, a greyish solid is obtained having a floury appearance. After vacuum-drying for six hours, a white powder is obtained. Analyses have shown that this is magnesium chloride in 8 form. B.6 - Examples of preparation of magnesium-based polymeric electrolytes Example B.6.1 - (Preparation of the polymeric electrolyte polyethylene glycol/(MgCI2)x) The magnesium salt is previously dissolved in ethyl acetate. In the same solvent, a polyethylene-glycol solution Is prepared separately. The two solutions thus obtained are mixed together. After heating for approximately one hour under reflux, the solvent is removed by subjecting it to a vacuum (10"3 mbar) and to heating to a temperature of approximately 100°C. Any traces of solvents that are left are subsequently eliminated under high-vacuum conditions (10"6 mbar) for approximately two days. Example B.6.2 - (Synthesis of electronic polymer polyethilene glycol- poymethilsiloxane) An amount of polymer polyethilene glycol-poymethilsiloxane is dissolved in ethyl alcohol perfectly anhydrous. Separately in the same solvent is prepared a solution of 8 magnesium chloride. Then the two solutions obtained are mixed together. the solvent is subsequently removed under vacuum (10~3 mbar)at temperatures from 80°to100°C. Example B.6.3 - (Synthesis of the electrolytic polymer obtained by doping the polyethylene-diaminotetra-acetate-polyethereal copolymer with magnesium salts) The synthesized polyethylene-diaminotetra-acetate-polyethereal copolymer is doped directly with magnesium salts at the melting temperature of the copolymer. Example B.6.4 - (Direct synthesis, i.e., without solvents, of polymeric electrolytes with a base of polyethylene glycols or polyethylene oxides and 8 magnesium chloride) The polyether polymers of various molecular weights (200 to 200.000) are directly treated with 8-MgCb. The heterogeneous system thus obtained is homogenized for complete dissolution of the salt in the polymer by means of heating and continuous stirring. Example B.6.5. - (Direct synthesis, i.e., without solvents, of polymeric electrolytes having a base of polyethylene glycols or polyethylene oxides and 8 magnesium chloride, acidified with P2O5) The polymeric electrolyte obtained according to the foregoing Example B.6.4 is treated with 8 wt% of P205. The time required for obtaining a polymeric electrolyte by means of stirring and complete dissolution of the P2Os is approximately 4 hours. The addition of P2O5 increases the viscosity of the polymer. BJ - Example of preparation of the polymeric electrolyte 12 reinforced with glass fibres The liquid polymeric electrolyte or solid polymeric electrolyte in the molten state is used for impregnating a glass-fibre fabric. In this way, a thin layer of polymeric electrolyte is obtained which is reinforced with glass fibres. C - Examples of prototypes produced Practical tests carried out on prototypes revealed that the task and purposes set had been achieved. In particular, in one first case (single-element button battery with polymeric electrolyte reinforced with a porous paper filter), an anodic disk (anode 10) made of sintered metallic magnesium and having a diameter of 8 mm was interfaced with a film of polymeric electrolyte PEG 400 (MgCl2)x reinforced with a paper disk having the same diameter, after prior heating of the two compounds. On top of the polymeric-electrolyte film was laid a composite cathodic film (cathode 11) having a base of intercalation material consisting of metal oxides with graphite in liquid suspension subsequently dried, prepared according to the previous examples. The element thus obtained was housed on a system consisting of two current collectors 13. A few instants after assembly, this prototype revealed a voltage of approximately 0.8 V. Within approximately 5-6 hours, the voltage of the battery prototype increased until it reached approximately 1.8 V. After a few rechargings were carried out at a constant current of between 5 and 150 \|iA, the prototype presented a threshold voltage between 2 and 3 V. After discharge, the voltage returned to 1.8 V. In a second case (single-element button battery with polymeric electrolyte reinforced with glass fibre), the anode 10 and cathode 11 were prepared according to the same procedures as for the first prototype. In the present case, as reinforcement for the polymeric electrolyte 12, glass fibre having a thickness of 0.02 mm was used. The characteristics of this prototype were the same as for those of the first prototype, but the reversibility was considerably superior. In a third case (single-element button battery with polymeric electrolyte acidified with P205 and reinforced with glass fibres), the anode 10 and cathode 11 were prepared following the same procedures as for the first prototype. Acidification of the polymeric electrolyte 12 by means of P2O5 enabled a voltage of approximately 2.2 V to be obtained, together with excellent reversibility, a high specific energy density, and a considerable charge capacity. From the examples given above there clearly emerge the advantages that may be obtained using magnesium for the production of the batteries that form the object of the present invention. In addition, when compared to lithium, magnesium, which is a very light element, presents characteristics of better workability, together with a good reactivity and oxide-reducing voltage. The possibility for magnesium to exchange two electrons may enable an efficiency of 100%, and, given the same volumes, magnesium may reach 80% more in terms of charge and 45% more in terms of energy as compared to lithium. The systems developed according to the technology described herein enable, in fact, excellent technical performance to be achieved, allied to the advantage of a reduction in production costs and to the practically total absence of environmental impact, given that the component materials are all non-polluting and that magnesium is a safe element as demonstrated by its medical and clinical uses. The invention thus conceived may undergo numerous modifications and variations, and, without departing from the scope of the inventive idea of the present invention, it is possible for a person skilled in the branch to make, to the primary (non-rechargeable) and secondary (rechargeable) batteries that form the object of the present invention, all the modifications and improvements resulting from normal technical know-how and experience in the sector, as well as from the natural evolution of the state of the art. WE CLAIM: 1. A primary (non-rechargeable) and secondary (rechargeable) batteries, of the type comprising at least one anode, at least one cathode, at least one electrolyte set between anode and cathode, and current collectors, said batteries being characterized in that at least: -the anode contains magnesium in the various states of oxidation Mgn+ (n+== °, 1+' ), optionally combined with metallic magnesium -the electrolyte contains as ionic species magnesium chlorides in 5 form having lattice energy lower than 500 kcal/mol in solvents capable of producing electrolytes having good ionic conductivity, and of solvating said species. 2. The batteries according to Claim 1, wherein also the cathode contains magnesium. 3. The batteries according to Claim 1, wherein the anode comprises metallic magnesium laminated or sintered. 4. The batteries according to Claim 1 wherein the anode comprises magnesium on a substrate of highly conductive organic or inorganic material chosen from among metals, oxides, alloys or fabrics thereof, carbon fibre and carbon fibre fabrics, graphite, or graphite-based composites. 5. The batteries according to Claim 1, wherein the anode comprises magnesium intercalated or embedded in highly conductive organic or inorganic materials, which intercalate or embed, in their own matrices, magnesium crystallites of reduced dimensions or magnesium monocrystals, chosen from among oxides, sulphides, phosphates or phosphides of transition metals, alkaline metals, and alkaline-earth metals, as well as non-metal compounds or having a base of carbons with a highly crystalline or irregular structure or carbon-based polymers. 6. The batteries according Claims 3 and 5 wherein the anode is oxidised with oxidising agents chosen from among oxygen gas, hydrogen peroxide, or organic peroxides. 7. The batteries according Claims from 3 to 6 wherein the anode is stabilized by treatment with alkoxides chosen from among tetra-alkoxy titanium, tetra-alkoxy silanes, trialkoxy aluminium, tetra-alkoxy zirconium, or magnesium dialkoxide. 8. The batteries according to Claim 1, wherein the electrolyte comprises as solvent any liquid or polymeric organic solvent material having polar groups or heteroatoms chosen from oxygen, nitrogen, silicon and phosporus which co-ordinate and dissociate the magnesium chlorides in 5 form. 9. The batteries according to Claim 8 wherein the electrolyte comprises as polymeric solvent polyalkylene glycols and or polyalkylene oxides. 10. The batteries according Claims 8 and 9, wherein the electrolyte is acidified with compounds having a base of phosphorus, polyphosphates, P2O5, or orthophosphoric acid. 11. The batteries according to Claims 8 and 9, wherein the electrolyte is alkalinized with compounds being a base or nitrogen such as amines and ammonia, or with basic derivatives of sulphur or phosphorus. 12. The batteries according to Claims 1 and 2 wherein the cathode comprises magnesium on a substrate of highly conductive organic or inorganic materials chosen from among metals, oxides, alloys or fabrics made of the same, carbon fibre and carbon-fibre fabrics, graphite or graphite-based composites. 13. The batteries according to Claims 1 and 2, wherein the cathode comprises magnesium in organic or inorganic materials that intercalate or embed magnesium chosen from among oxides, sulphides, phosphates or phosphides of transition metals, alkaline metals, and alkaline-earth metals, as well as non-metal compounds or having a base of carbons with a highly crystalline or irregular structure or carbon-based polymers. 14. The batteries according Claims 12 and 13 wherein the cathode is oxidised with oxidising agents chosen from among oxygen gas, hydrogen peroxide, or organic peroxides. 15. The batteries according Claims 12 and 13 wherein the cathode is prepared with electrochemically active material partially oxidised with oxidising agents chosen from among oxygen gas, hydrogen peroxide, or organic peroxides. 16. The method for the production of batteries according to Claim 1, wherein it envisages of the following step: -preparation of an anode wherein it comprises magnesium in the various states of oxidation Mgn+(n+== °' 1+' 2+), optionally combined with metallic Mg, said anode having a base of metallic magnesium, or else of magnesium on a substrate of highly conductive inorganic or organic materials, or in inorganic or organic materials for intercalation or embedding of the magnesium and -preparation of an electrolyte wherein it comprises as ionic species magnesium chlorides in 8 form in solvents that are capable of producing electrolytes having good ionic conductivity and of solvating said species and optionally -preparation of a cathode wherein it comprises species of magnesium having a substrate of highly conductive inorganic or organic materials or in inorganic or organic materials for intercalation or embedding of the magnesium. 17. The method for the production of batteries according to Claim 16, wherein the anode is prepared from laminated or sintered metallic magnesium. 18. The method for the production of batteries according to Claim 16, wherein the anode having a base of magnesium on a substrate is prepared by chemical or thermal vapour deposition, or electrolytic deposition, or electrochemical deposition of the magnesium on organic or inorganic materials chosen from among metals, oxides, alloys or fabrics made of the same, carbon fibre carbon fibre fabrics, graphite, or graphite-based composites. 19. The method for the production of batteries according to Claim 16, wherein the anode with a base of magnesium in intercalation or embedding material is prepared by (i) homogenization and pelletization of a mixture of an intercalation or embedding material, ground up to complete structural disorder, and magnesium carbonates or oxides brought up to a temperature of between 100 and 400°C for a period of time of between 1 and 3 hours, (ii) then heating up to temperatures of between 800 and 1200°C in an inert atmosphere, (iii) and finally keeping at this temperature for 1-5 days in vacuum conditions. 20. The method for the production of batteries according to Claim 16, wherein the anode with a base of magnesium in intercalation or embedding material is prepared by solvent-casting of a solvent such as benzene, toluene, N-N dimethyl acetamide, dimethyl formamide, or tetrahydrofuran, containing, in a homogeneous way, a mixture of polymers chosen from among polyethylene, polyvinyl chloride, polyacrylamide or polyacrylonitrile, or similar polymers, and the intercalation or embedding material chosen, previously extended up to complete homogenization with magnesium. 21. The method for the production of batteries according to Claim 16, wherein the anode with a base of magnesium in intercalation or embedding material for intercalating or embedding magnesium is prepared by plasma spraying or sputtering of the magnesium into the intercalation or embedding material chosen. 22. The method for the production of batteries according to any one of Claims 16-21, wherein the anode is oxidised with oxidising agents chosen from among oxygen gas, hydrogen peroxide, or organic peroxides. 23. The method for the production of batteries according to any one of Claims 16-22, wherein the anode is stabilized by treatment with alkoxides chosen from among tetra-alkoxy titanium, tetra-alkoxy silanes, trialkoxy aluminium, tetra-alkoxy zirconium, or magnesium dialkoxide. 24. The method for the production of batteries according to Claim 16, wherein the electrolyte is prepared by direct dissolution of the 8-magnesium chlorides in the liquid solvent or molten polymer. 25. The method for the production of batteries according to Claim 16, wherein the electrolyte is prepared by solvent-casting of the common solvent of the polymer and of the 8- magnesium chlorides. 26. The method for the production of batteries according to Claim 16, wherein the electrolyte is prepared by dissolution of the 5-magnesium chlorides in one or more monomers and by subsequent polymerization. 27. The method for the production of batteries according to Claim 16, wherein the cathode having a base of magnesium on a substrate is prepared by chemical or thermal vapour deposition, or electrolytic deposition, or electrochemical deposition of the magnesium on organic or inorganic materials chosen from among metals, oxides, alloys, or fabrics made of the same, carbon fibre, carbon fibre fabrics, graphite, or graphite-based composites. 28. The method for the production of batteries according to Claim 16, wherein the cathode with a base of magnesium in intercalation or embedding material is prepared by: (i) homogenization and pelletization of a mixture of an intercalation or embedding material, ground up to complete structural disorder, and magnesium carbonates or oxides brought up to a temperature of between 100 and 400°C for a period of time of between 1 and 3 hours, (ii) then heating up to temperatures of between 800 and 1200°C in an inert atmosphere, (iii) and finally keeping at this temperature for 1-5 days in vacuum conditions. 29. The method for the production of batteries according to Claim 16, wherein the cathode with a base of magnesium in intercalation or embedding material is prepared by solvent-casting of a solvent such as benzene, toluene, N-N dimethyl acetamide, dimethyl formamide, or tetrahydrofuran, containing, in a homogeneous way, a mixture of polymers chosen from among polyethylene, polyvinyl chloride, polyacrylamide or polyacrylonitrile, or similar polymers, and the intercalation or embedding material previously extended up to complete homogenization with magnesium. 30. The method for the production of batteries according to Claim 16, wherein the cathode with a base of magnesium in intercalation or embedding material is prepared by plasma spraying or sputtering of the magnesium into the intercalation or embedding material chosen. 31. The method for the production of batteries according to any one of Claims 27-30, wherein the magnesium of the cathode is oxidized with oxidising agents chosen among from oxygen gas, hydrogen peroxide, or organic peroxides. 32. The method for the production of batteries according to any one of Claims 27-30, wherein the cathode is prepared with electrochemically active materials previously partially oxidized with oxidising agents chosen among from oxygen gas, hydrogen peroxide, or organic peroxides. 33 The method for setting magnesium batteries according to any one of preceding claims, wherein at least one anode, at least one cathode, at least one electrolyte, current collectors and optionally dielectric spacers are put in contact between one another, setting the electrolyte between anode and cathode at temperatures of between room temperature and approximately 150°C.

Full Text

Scope of the invention
The present invention regards primary (i.e., non-rechargeable) and secondary
(i.e., rechargeable) batteries in which at least the anode contains magnesium, and
optionally also the electrolyte and cathode contain magnesium, as well as
methods for making said batteries.
Prior art
As is known, the enormous and rapid development of digital electronics that has
taken place in recent years has enabled the creation of a large number of new
portable devices, such as computers, cellphones, videocameras, etc. These
devices are almost exclusively equipped with storage batteries built according to a
single technology; namely nickel-cadmium (Ni-Cd) batteries.
The need to produce ever smaller and lighter portable devices, together with the
need for long operating autonomy of these devices, has pushed numerous private
firms operating in the sector, as well as public research bodies, to cany out
research aimed at developing new technologies capable of meeting the
requirements referred to above.
In the late eighties and early nineties, two new types of batteries appeared on the
market: nickel-metal hydride (Ni-MH) and lithium-ion (Li-ion) batteries.
In just a few years, the performance of batteries produced using these
technologies has improved considerably, to the extent that today the performance
of these batteries is superior to that of nickel-cadmium batteries.
A further advantage of the batteries produced using these new technologies is the
absence of cadmium, which, since it is a heavy metal, has quite a serious
detrimental impact on the environment.
As is known, lithium-ion batteries are, in energy terms, still the most promising
ones, but their production cost is relatively high. However, if the cost per cycle of
these systems is considered, it may be noted that they become competitive as
compared to the more economical nickel-cadmium batteries. On the basis of the
technical characteristics, environmental impact, and cost per cycle, a considerable
growth is expected for the lithium-ion system on the world market.

On the other hand, nickel-metal hydride batteries are likely to have a more modest
growth, whilst it is estimated that nickel-cadmium batteries are unlikely to maintain
their current production levels.
The international scenario witnesses a concentration of the majority of production
in the sector of lithium-ion batteries, which are an evolution of lithium systems.
Primary lithium batteries, which are widely used in calculators, clocks and
watches, cardiac pacemakers, etc., are made with a lithium anode and a cathode
made of transition metal oxide (e.g., Mn02). Thanks to the high electrochemical
potential supplied by the lithium anode, these batteries provide high cell voltages,
and consequently also high energy densities.
However, these systems are not reversible, or at the most are usable for just a few
cycles.
The idea of exploiting lithium to make secondary batteries has given rise to a first
technology known as lithium-polymer (Li-polymer) technology. This method, which
exploits metallic lithium for making the anode, presents, however, serious
difficulties in terms of reversibility. In fact, during the recharging phase, dendritic
deposits are formed on the surface of the anode, which are the result of the
reaction of the lithium with the organic polymeric electrolyte and are responsible
for the fast deterioration of this type of battery.
At best, the number of cycles obtained using systems of this type thus amounts to
just a few dozens or hundreds.
On the other hand, the reactivity of the lithium in regard to the polymeric electrolyte
may also become a cause of serious problems of safety in the operating phase of
the battery itself.
The next step in the development of these devices was that of the introduction of
the so-called lithium-ion or rocking-chair technology, which is based on solutions
that tend to solve the problem of formation of dendrites on the lithium anode by
replacing the lithium with composite materials capable of intercalating Li* in their
structure via insertion reactions.
In recent years, it has been possible to produce anodes based on carbon with
properties of intercalation. Certain carbons with a regular structure (turbostatic or
graphitizabie) or with a highly crystalline structure (natural or synthetic graphites)

can in fact intercalate the Li4 ion in their layers in a reversible manner, thus giving
rise to complexes of the LixC6 type.
Other lithium-ion batteries are provided with an intercalated titanium disulphide-
based (LixTiS2) anode. The latter has a behaviour similar to that of a carbon
electrode.
Usually the cathode is instead made using oxides of lithium and transition metals,
among which the most widely used up to now is lithium cobaltate (UC0O2), which,
for reasons of cost, availability, and toxicity, tends to be replaced by lithium
nickelate (LiNi02) or lithium manganate (LiMn04).
The number of cycles achievable using the rocking-chair technology reaches one
thousand.
Usually, in these systems the electrolyte consists of an organic polymer with
solvent properties, which is rendered ionic-conductive by being doped with special
lithium salts (e.g., LiPF6f LiCI04f etc.).
Notwithstanding the fact that the above-mentioned technological advances tend to
solve the problems linked to the use of lithium on account of the high reactivity of
this element, and in particular the main problem linked to the formation of
dendrites on the anode, research for a complete solution to these problems is still
very much in progress. The problem of the formation of dendrites has not yet been
completely solved, whilst likewise the problem of high reactivity of lithium, together
with the known problems of safety referred to previously, and the problem of
reversibility still remain open.
Magnesium could be an element usable for overcoming these problems, and in
particular as a replacement for lithium.
As reported in the literature, a number of researchers, such as Farrington and
Cherng have sought to develop magnesium-based polymeric electrolyte systems
for the possible development of magnesium batteries, with, however, somewhat
meagre results. The polymeric electrolytes obtained had, in fact, conductivities
which, at room temperature, were too high (i.e., with conductivity lower than 10"6
siemens/cm) for the production of primary and/or secondary batteries.
Nevertheless, in the patent US44575 Moulton suggests the possibility of making
magnesium batteries, without, however, specifying the procedure, in particular

without specifying how to make the anode, cathode and polymeric electrolyte. Polymeric electrolytes doped with magnesium salts are cited, which, when tested, yielded resistivities higher than 107 ohm.cm at room temperature, whereas in order to be able to make the batteries it.is necessary for the resistivity values to drop below than 105 ohm*cm.
The main task of the present invention is to succeed in developing primary (non-rechargeable) batteries and/or secondary (rechargeable) batteries that overcome the problems of reactivity and reversibility typical of lithium-based batteries. In the framework of the above-mentioned task, a consequent primary purpose is to develop batteries with high-level technical characteristics allied to a reduction in production costs.
Another important purpose is to develop miniaturized and lightweight batteries. Yet a further purpose is to develop batteries suitable for use in portable digital electronic equipment.
A further important purpose is to arrive at the almost total elimination of environmental impact. Summary of the invention
These and other purposes, which will appear more clearly in what follows, are achieved by primary (non-rechargeable) and secondary (rechargeable) batteries that form the object of the present invention, of the type comprising at least one anode, at least one cathode, at least one electrolyte, and current collectors, said batteries being characterized in that at least the anode and preferentially ajso the electrolyte contain magnesium. Also the cathode of the batteries that form the object of the present invention may optionally incorporate magnesium. The anode included in the present invention is characterized in that it uses magnesium in the various states of oxidation Mgn+(0~n£2), optionally combined with metallic magnesium, and the electrolyte, possibly containing- magnesium, is characterized in that it comprises any ionic species of magnesium in solvents, including polymeric solvents, that are capable of producing electrolytes having good ionic conductivity and capable of solvation of the said ionic species. i/Vhen the cathode contains magnesium, this is a species of magnesium in the state of oxidation 2+ and may have a substrate of highly conductive inorganic or

organic materials, or else may be intercalated or embedded in highly conductive inorganic or organic materials.
Forming a further object of the present invention are methods for the production of said primary and secondary batteries of the type comprising at least one anode, at least one cathode, at least one electrolyte set between anode and cathode, and electrical-connection collectors, said batteries being characterized in that at least the anode and the electrolyte contain magnesium and even the cathode can optionally contain magnesium.
Brief description of the figure
Figure 1 is a schematic sectional view of a battery built according to the present
invention, where:
10 designates an anode which has the characteristics and is made as is described in detail in what follows;
11 designates a cathode which has the characteristics and is made as is described in detail in what follows;
12 designates an electrolyte which has the characteristics and is made as is described in detail in what follows and
13 designates current collectors which have the characteristics and are made as is described in detail in what follows:-
Detailed description of the invention
Notwithstanding the fact that the attempts referred to above failed to lead to promising
results, the present inventors have now surprisingly found that magnesium is an
element that can be usefully employed in making primary and secondary batteries.
Following on extensive and ample research, the present inventors have in fact found
that, for the purposes of the present invention, i.e., for obtaining primary and
secondary batteries with technical performance comparable, if not superior, to that of
lithium batteries at present in use or known, reference being made to the —

aforementioned Figure, the batteries that form the object of the present invention may be primary and secondary batteries of the type comprising at least one anode, at least one cathode, at least one electrolyte set between anode and cathode, and current collectors, said batteries being characterized in that at least the anode and preferentially also the electrolyte contain magnesium. ' In the batteries that form the object of the present invention also the cathode may optionally incorporate magnesium.
When the cathode does not contain magnesium, it is a conventional cathode, and hence is in itself known, and consequently will not be described further herein. The primary and secondary batteries that form the object of the present invention may moreover comprise possible dielectric spacers, not illustrated in the Figure. In particular, the batteries according to the present invention may be made up of:
An anode 10 characterized in that it comprises magnesium in the various states of oxidation Mgn+{0*n*2,f optionally combined with metallic magnesium.
In said anode, the magnesium may be included as such or may also have a substrate of highly conductive inorganic or organic materials, or else of highly conductive inorganic or organic materials that are capable of englobing, by intercalation or embedding into their own matrices, magnesium crystallites of reduced dimensions or magnesium monocrystals.
In particular, the anode 10 may consist of metallic magnesium as such, and in this case the magnesiurrrmay be used in laminated or sintered form. In the case, instead, where the magnesium has a substrate of highly conductive materials, these may be inorganic materials chosen from the group made up of metals, for example aluminium, copper, and other equivalent metals, or oxides, alloys, and fabrics made of the same. The said highly conductive substrate materials may also be organic, and also of a polymeric type; in the latter case, they are chosen from among materials such as carbon-fibre fabrics, graphite, or even graphite-based composite materials, or other equivalent materials suitable for the purposes.
Also in the case where intercalation or embedding materials are used for the .anode, this may be either organic or inorganic. The intercalation or embedding

materials that may be used for the purposes of the present invention are transition-metal compounds, alkaline-metal compounds, and alkaline earth-metal compounds, as well as non-metal compounds, chosen from among oxides, sulphides, phosphates or phosphides, such as tungsten oxides (WyOx), ferric oxides (FeyOx), titanium sulphides (TiySx), cobalt oxides (CoyOx), nickel oxides (NiyOx), manganese oxide (MnyOx), or else other equivalent compounds, or carbon-based materials with intercalation properties and with a highly crystalline structure or an irregular structure, or equivalent materials, or else a material of a polymeric type, such as carbon-based polymers or equivalent polymers that are capable of englGbjngl_b_y_jotercaIation.jDr_embedding. into._their_.own. matrices, magnesium crystallites of reduced dimensions or magnesium monocrystals. Furthermore said anode 10 may be optionally oxidized with oxidizing agents such as oxygen gas or peroxide, such as H2O2, or organic peroxides and stabilized by treatment with stabilizing agents such as alkoxides, (e.g. tetra-alkoxy titanium, tetra-alkoxy silanes, trialkoxy aluminium, tetra-alkoxy zirconium, or magnesium dialkoxide, or equivalent compounds).
A cathode 11 characterized in that it contains magnesium species with state of oxidation 2*.
In the case where the cathode contains magnesium, the latter may have a substrate of highly conductive inorganic or organic materials, including polymeric materials, or else the magnesium may be intercalated or embedded in inorganic or organic materials. The materials that may be used both in the case where the magnesium has a substrate and in the case where the magnesium is intercalated or embedded are the same as the materials mentioned previously for the anode. This type of cathode may be used, dispersing the active material in a porous and conductive matrix. This use affords the advantage of improving the electrochemical properties of the batteries.
Also the cathode may be optionally oxidized with the same oxidizing agents. The oxidation of the cathode may be, like the anode, in situ and following on its preparation or, unlike the anode, the cathode may be prepared with electrochemically active materials that have been partially oxidized prior to its preparation.

When the cathode 11 does not contain magnesium, it is a conventional cathode and is in itself known; consequently, it is not further described herein. In this case, anyway, the cathode contains electrochemically active materials having a base of metallic mixtures in appropriate proportions in a reduced or oxidized form. For this purpose, as is known from the prior art, materials containing transition metals may be used, such as, but not exclusively, manganese with state of oxidation ranging from 7* to 2+, and other equivalent metals.
An electrolyte 12 characterized in that it comprises any ionic species of magnesium in solvents, including polymeric solvents, capable of producing electrolytes with good ionic conductivity and capable of solvating said species. The electrolyte according to the present invention comprises, as tonic species of magnesium, magnesium salts or complexes of the general formula Mg(R)yX2-y, with 0 The radical R may be chosen from the group consisting, for example, of alkyls with C1-C7 chains, whilst X may be chosen from among halides, CI04, (CF3)i*xS03-x, with 0 The solvents used for the^ electrolyte may be of various types, since the essential characteristic required is that they should possess good ionic conductivity and in any case that they should at the same time be able to solvate the magnesium salts or magnesium complexes that have been chosen. For the purpose, they may therefore be liquid solvents or solvents in the solid or viscous state. In the case of liquid solvents, these are chosen from among materials having polar groups which are able to co-ordinate and dissociate the ionic magnesium salts or complexes and which contain oxygen, nitrogen, sulphur and carbon. These solvents may therefore be chosen from among ethers, alcohols, di-alcohols, esters, amines and amides, thioethers, thioalcohols, thioesters, alkyl carbonates and alkyl thiocarbonates, or other equivalents.
In the case where the solvent for the electrolyte is solid or viscous, it may be of a polymeric type.

Jsable for the purpose are all the polymers or copolymers of the same having jifferent molecular weights, which are capable of solvating magnesium salts or :omplexes suitable for the purpose. Such polymers and/or copolymers may be chosen from among polyaikylene oxides, polyalkylene glycols, polycarbonates, polyalkyl siloxanes, polyethylene diaminotetra-acetate, or equivalent polymers or copolymers of the same macromolecular frameworks having different molecular weights, also containing, in their chains, hetero-atoms of the oxygen, nitrogen, silicon, and phosphorus types.
Also usable for the purpose are polyphosphazene polymers functionalized with the polymers and/or copolymers mentioned previously.
To provide examples, among polyalkylene oxides, the following may be mentioned: polymethylene oxide, polyethylene oxide, polypropylene oxide and others; among polyalkylene glycols, the following may be mentioned: polymethylene glycols, polyethylene glycols, polypropylene glycols and fluorinated derivatives of the same and others; among polycarbonates, the following may be mentioned: polymethylene carbonates, polyethylene carbonates, and polypropylene carbonates and others; among the polyalkyl siloxanes, the following may be mentioned: polymethyl siloxane, polyethyl siloxane, and polypropyl siloxane and others.
Also usable for the purpose are copolymers derived from the polyalkylene oxides and polyalkylene glycols, polycarbonates, polyalkyl siloxanes, polyethylene diaminotetra-acetate; polyalkylene glycols and polycarbonates, polyalkyl siloxanes, polyethylene diaminotetra-acetate; polycarbonates and polyalkyl siloxanes, polyethylene diaminotetra-acetate; polyalkyl siloxanes and polyethylene diaminotetra-acetate such as, as example, polyethylene oxide-polypropylene oxide, polymethylene oxide-polyethylene oxide, and polymethylene oxide-polypropylene oxide; polyethylene oxide-polymethylene carbonate, polypropylene oxide-polyethylene carbonate, and polyethylene oxide- polypropylene carbonate; polyethylene glycol- polymethyl polysiloxane, polyethylene oxide-polymethyl siloxane, and polyethylene oxide- polyethylene diaminotetra-acetate, etc. It is also possible to use for the purpose, for instance, polyphosfihazene polymers functionalized with polymers and/or copolymers of the polyethylene-oxide type or

the like having different molecular weights.
The polymers and/or copolymers that may be used for the preparation of the
electrolyte may moreover be functionalized with groups that bond or co-ordinate
magnesium so as to improve their interaction with the salts or complexes of the
latter.
For the purpose of improving the ionic conductivity of the electrolyte, this may also be optionally acidified or alkaiinized according to known procedures, which, consequently, will not be described in greater detail herein. In the case where the electrolyte is acidified, however, the preferential acidifying agents for the electrolyte are compounds with a base of phosphorus, polyphosphates, P2O5, or equivalents of the orthophosphoric-acid type. In the case where the electrolyte is alkaiinized, the compounds that may be used are nitrogen-based ones and, in this case, are preferentially amines or ammonia, as well as basic derivatives of sulphur and phosphorus.
Acidification improves the conductivity of the electrolyte, and this process is to be carried out whenever the performance of the electrolyte is not adequate for the application. This process is to be preferred in the case of stabilized electrodes. Also alkalinization improves the conductivity of the electrolyte and is carried out with the purpose of favouring the electrochemical functioning of the electrodes. This process is, however, to be preferred in the case where non-stabilized electrodes are used.
Spacers (not shown in the Figure) consisting of inorganic or organic materials which are permeable to ions and have high dielectric characteristics; these are appropriately functionalized, if necessary, in order to eliminate the polar groups that may be present on the surfaces of the fibres. For the purpose it is possible to use, for example, cellulose, glass-fibre fabrics, organic membranes, or other equivalent materials.
Current collectors 13, either metallic or non-metallic, with conductive characteristics and with a resistivity of not more than 10 ohm»m for collecting the electrons and for electrical connection of the poles of the battery element. For the purpose, it is possible, for example, to use metals, even in the form of oxides, alloys, and fabrics made of the same, such as aluminium, copper, steel, brass,

etc., or organic materials made of carbon or carbon-fibre fabrics, or similar
materials.
The method for making the primary and/or secondary batteries according to the
present invention envisages at least one of the following steps:
- preparation of an anode characterized in that it comprises magnesium in the various states of oxidation Mgn+ ((Kn*2), optionally combined with metallic Mg, said anode having a base of metallic magnesium as such, or else of magnesium on a substrate of highly conductive inorganic or organic materials, or in inorganic or organic materials for intercalation or embedding of the magnesium;
- preparation of a cathode characterized in that it comprises species of magnesium in the state of oxidation 2* having a substrate of highly conductive inorganic or organic materials or in inorganic or organic composite materials for intercalation or embedding of the magnesium;
- preparation of an electrolyte characterized in that it comprises any ionic species of magnesium in solvents that are capable of producing electrolytes having good ionic conductivity and of solvating said species.
The electrolyte may moreover optionally be reinforced with spacers as described
previously.
The above three components are put in contact with one another, the layer of
electrolyte 12 being set irLbetween the anode 10 and the cathode 11. The intimate
contact between anode 10, electrolyte 12, and cathode 11 may also be obtained
by exerting a slight pressure on the ensemble of components at temperatures of
between room temperature and approximately 150°C.
To obtain batteries with adequate performance, the same technologies may be
adopted as those used for the preparation of the already known lithium batteries.
In particular, it is possible to:
- use single-layer or multi-layer button battery technology;
- connect the multi-layer films in parallel (parallel stacking), or else connect the multMayer films in series (bipolar stacking), for non-folded structures;
- use flat-roll design technology or jelly-roll design technology, or flat-stack design technology for folded structures.
Described in detail in what follows are the methodologies for the preparation of the

individual components when these contain magnesium, and hence are not
conventional and so known, both in terms of characteristics and in terms of
production methodologies, to any person skilled in the branch.
A - General methodologies for the preparation of the components
A. 1 - Preparation of the anode 10
For the purposes of the present invention, three types of anode 10 may be used: a
magnesium-based anode having the characteristics already mentioned previously,
(i) as such or (ii) on a substrate of highly conductive organic or inorganic materials,
or (iii) intercalated or embedded in material for intercalation or embedding of
magnesium.
The magnesium as such may be laminated starting from Grignard-grade
magnesium, or may be in the form of powder of appropriate grain size, or else in
the form of a ribbon of varying length, which is commercially available. In addition,
the magnesium may also be sintered.
The anode may also consist of magnesium on a substrate of highly conductive
organic or inorganic materials, including polymeric materials, as described
previously. This type of anode may be prepared by chemical, thermal vapour,
electrolytic, or electrochemical deposition methods of magnesium species.
The other type of anode 10 is made with intercalation or embedding material for
magnesium. Particularly this anode is prepared by suspending, in a solvent such
as benzene, toluene, N-N dimethyl acetamide, dimethyl formamide, or
tetrahydrofuran or the like, a mixture of polyethylene or polyvinyl chloride, or
polyacrylamide, or polyacrylonitrile, or some other, with intercalation material
previously extended up to complete homogenization with magnesium. The system
is treated until complete and homogeneous distribution of the above described
materials in the solvent itself is obtained. The composite film with a base of
intercalation or embedding material is then obtained by slow evaporation of the
solvent.
Other methods of intercalation, in addition to the ones described previously, for
obtaining the anode, may be based on physical methodologies, such as plasma
spraying or sputtering of the magnesium into the intercalation or embedding
material chosen.

Whatever the type of anode, this may possibly be subsequently oxidized with oxygen gas or peroxide, such as H2O2, or organic peroxides. The anode may, moreover, be subjected to a further and possible stabilization treatment. As stabilizing agents may be used alkoxides, such as tetra-alkoxy titanium, tetra-alkoxy silanes, trialkoxy aluminium, tetra-alkoxy zirconium, or magnesium dialkoxide, or other equivalent compounds.
With the above further processes it is possible to obtain an anode that presents better characteristics of stability, reversibility, and exchange currents. A.2 - Preparation of the cathode 11
The cathode 11 may be prepared either providing a substrate for the magnesium or with a composite having a base of intercalation or embedding material, adopting methodologies that are similar to the ones already described for the anode 10, and which, for this reason, will not be described further herein. The intercalation materials are the same as those usable for the anode and may be, for example, but not exclusively, with a base of carbon, graphite, titanium disulphide (TiS2), cobalt dioxide (Co02), nickel dioxide (NiC^). manganese dioxide (MnOa), or other equivalents chosen from among the ones already mentioned previously. Like the anode, also the cathode may undergo further processes of oxidation in situ and following on its preparation, these processes having already been described previously. Unlike the anode, however, the cathode may be prepared with electrochemically active materials that have been partially oxidized prior to the preparation of the cathode. A.3 - Preparation of the intercalation material
The intercalation material is chosen from among the materials that may be used for this purpose in the anode or in the cathode, and is prepared according to the general procedure described in what follows. The intercalation material is ground in a ball mill until complete structural disorder of the material is achieved. Subsequently, the material is brought into intimate contact with magnesium carbonates or magnesium oxides. The mixture thus obtained, after homogenization and peptization is brought up to a temperature of approximately 100°C to 400°C for a period of between 1 and 3 hours, and subsequently to a temperature of between 800°C and 1200°C under a inert atmosphere (for

example, an argon atmosphere), and then kept at the temperature range indicated in vacuum conditions for 1 to 5 days. A.4 - Preparation of the electrolyte 12
The electrolyte 12 according to the present invention may be prepared using solvents, including, but not exclusively, polymeric solvents, capable of solvating any ionic species of magnesium and of producing electrolytes having good ionic conductivity. The electrolyte according to the present invention comprises, as ionic species, magnesium salts or magnesium complexes of the general formula Mg(R)yX2-y, with 0 electrolyte
The mode of preparation of the electrolyte 12 according to the above reaction can follow three general procedures. The first regards the direct dissolution of the magnesium salt or complex in the liquid solvent or in the melted polymer (when the latter so permits). The second procedure regards the dissolution of the polymer solvent and the magnesium salt or complex in a common solvent to obtain the polymeric film through slow evaporation of the solvent (solvent-casting). The third procedure regards obtaining polymeric electrolytes which can have a high conductivity and which are based on polymeric electrolytes having a high degree of crosslinking. In these circumstances, the polymeric electrolyte, for obvious reasons, must be prepared obtaining solutions of the monomer and of the magnesium salt or complex preliminarily, and carrying out the polymerization reaction subsequently.
The solvents usable for the purpose are a\\ those already mentioned previously, and in particular, to provide an example, any liquid material having polar groups containing oxygen, nitrogen, sulphur, and carbon, which co-ordinate and

dissociate the ionic magnesium salts or complexes, such as ethers, alcohols, di-alcohols, esters, amines and amides, thioethers, thioalcohols, thioesters, alkyl carbonates and alkyl thiocarbonates, or else polymers and/or copolymers with different molecular weights, polyalkylene oxides, polyalkylene glycols, polycarbonates, polyalkyl siloxanes, polyethylene diaminotetra-acetate, derivatives thereof in which one or more atoms in the chain are substituted with one or more hetero-atoms chosen from among oxygen, nitrogen, silicon, and phosphorus and polyphosphazene polymers functionalized with the polymers or copolymers mentioned previously.
Among the magnesium salts or complexes that may be used for the purposes of the present invention, particularly advantageous is 5-MgCI2, which, since It has a very low lattice energy, i.e., close to 0 kcal/moL, may be solubilized in organic solvents that are capable of co-ordinating the magnesium, and Grignard magnesium as species generating cations for the electrolyte. The electrolyte obtained according to one of the processes described above may also be acidified or alkalinized with the use of procedures and means known for the purpose. In the case where the electrolyte is acidified, it may be preferential for the purposes of the present invention to add appropriate amounts of phosphorus-based compounds, such as P2O5, or other equivalents, under stirring and up to complete dissolution. A^similar procedure is followed in the case where the electrolyte is alkalinized with nitrogen-based compounds or with basic derivatives of sulphur and phosphorus. A.5 - Preparation of the dielectric spacers
The dielectric spacers may be made of any ion-permeable insulating materials having good characteristics of insulating strength and dielectric constant. In the case where the material has polar groups on its surface, chemical inertization is performed by means of appropriate functionalization to prevent interaction with the magnesium ions or with ionic complexes of magnesium. In the case of glass fibres, for example, the hydroxyl groups present on the surface are de-activated by reaction with triethoxyalkyl silane, thus rendering the surface of the spacer highly apolar. B - General examples for the production of the components

The invention is hereinafter further clarified in its general aspects and through a
few examples of practical implementation, which have the sole purpose of
illustrating the invention without limiting the scope thereof in any way,
B.1 - Example of preparation of the anode 10 by sintering
The anode 10 is prepared starting from metallic magnesium which is finely ground
and sintered applying a pressure of 1400 MPa. In this way, after applying the
pressure for approximately 10 minutes, a metallic film is obtained having the
desired thickness.
B.2- Preparation of graphite thermally pre-intercalated with magnesium
A mixture of magnesium oxide and graphite, in a weight ratio ca of 3% is rendered
disordered using a ball mill. This mechanical mixing proceeds for approximately
thirty minutes and has the purpose of intimately homogenizing the two
components. The mechanical action of the mill moreover increases the
crystallographic disorder of the graphite. The material thus obtained is next
introduced into a quartz tube and subjected to six nitrogen-vacuum cycles to
eliminate any traces of air.
Subsequently, the tube is subjected to a vacuum by means of a diffusion pump at
a pressure of 10"6 mbar and brought up to a temperature of 700°C, at which it is
kept for approximately 14 hours.
B.3 - Preparation of the composite cathode 11
The intercalated graphite, referred to in Example B.2, is suspended in a xylene
solution containing, dissolved therein, 10 wt% of polyethylene. From the mixture
thus obtained the solvent is made to evaporate slowly (solvent-casting method) to
obtain a black, slightly gummy film, which is broken up into tiny flakes and
subsequently converted into a sintered cathode 11 by application of a pressure of
1400 MPa.
BA- Examples of preparation of the polymers for the electrolyte
Example B.4.1
Commercially available polyethylene glycols with molecular weights from 200 up to
1000 maybe used.
Example B.4.2
For the preparation of the polymer, it is possible to use commercially available

polymers, such as polycarbonates, or equivalent ones.
Example B.4.3 - (Synthesis of polyethylene glycol-polydimethyl polysiloxane
copolymers)
An aliquot of approximately 3 grams of dimethyl dichlorosilane is made to react in toluene with 50 mol% of polyethylene glycol 400. The reaction is conducted in nitrogen for approximately 10 hours. A transparent polymer is obtained having a high viscosity. After eliminating the toluene and the residue of dimethyl dichlorosilane in vacuum conditions (10"3 bar) at a temperature of approximately 120°C, a thick liquid polymer is obtained that resembles honey in appearance. The analyses have shown that the material thus synthesized is a copolymer with blocks of polyethylene oxide and polydimethyl siloxane.
Example B.4.4 - (Synthesis of the di-anhydride monomer of ethylene-diaminotetra-acetate acid)
Approximately 3 grams of ethylene-diaminotetra-acetate acid are made to react in toluene with acetic anhydride in the presence of small amounts of pyridine. After approximately two hours of refluxing, the white precipitate of the anhydride of the ethylene-diaminotetra-acetate acid is first filtered and then washed with toluene in a rigorously inert nitrogen atmosphere. The white solid thus obtained is subsequently vacuum-dried for approximately one day. The analyses have shown that the product is the anhydride of pure ethylene-diaminotetra-acetate acid. Example B.4.5 - (Synthesis of copolymer with blocks of ethylene-diaminotetra-acetate - polyethylene glycol)
The anhydride of the ethylene-diaminotetra-acetate acid is made to a react with a 1:1 aliquot of polyethylene glycol having a molecular weight of from 400 to 800. B. 5- Example of preparation of S magnesium chloride
One gram of metallic magnesium is introduced into a 250-ml flask in a rigorously inert argon atmosphere. The flask is prepared in an argon dry box with reflux drip and vacuum cocks. Approximately 100 ml of n-chlorobutane are added to the magnesium using the drip. The mixture thus obtained is made to react for approximately 8 hours under argon flow at the boiling temperature of the chlorobutane. After two hours' reaction, a greyish solid is obtained having a floury appearance. After vacuum-drying for six hours, a white powder is obtained.

Analyses have shown that this is magnesium chloride in 8 form.
B.6 - Examples of preparation of magnesium-based polymeric electrolytes
Example B.6.1 - (Preparation of the polymeric electrolyte polyethylene
glycol/(MgCI2)x)
The magnesium salt is previously dissolved in ethyl acetate. In the same solvent, a
polyethylene-glycol solution Is prepared separately. The two solutions thus
obtained are mixed together. After heating for approximately one hour under
reflux, the solvent is removed by subjecting it to a vacuum (10"3 mbar) and to
heating to a temperature of approximately 100°C. Any traces of solvents that are
left are subsequently eliminated under high-vacuum conditions (10"6 mbar) for
approximately two days.
Example B.6.2 - (Synthesis of electronic polymer polyethilene glycol-
poymethilsiloxane)
An amount of polymer polyethilene glycol-poymethilsiloxane is dissolved in ethyl
alcohol perfectly anhydrous. Separately in the same solvent is prepared a solution
of 8 magnesium chloride. Then the two solutions obtained are mixed together. the
solvent is subsequently removed under vacuum (10~3 mbar)at temperatures from
80°to100°C.
Example B.6.3 - (Synthesis of the electrolytic polymer obtained by doping the
polyethylene-diaminotetra-acetate-polyethereal copolymer with magnesium salts)
The synthesized polyethylene-diaminotetra-acetate-polyethereal copolymer is
doped directly with magnesium salts at the melting temperature of the copolymer.
Example B.6.4 - (Direct synthesis, i.e., without solvents, of polymeric electrolytes
with a base of polyethylene glycols or polyethylene oxides and 8 magnesium
chloride)
The polyether polymers of various molecular weights (200 to 200.000) are directly
treated with 8-MgCb. The heterogeneous system thus obtained is homogenized
for complete dissolution of the salt in the polymer by means of heating and
continuous stirring.
Example B.6.5. - (Direct synthesis, i.e., without solvents, of polymeric electrolytes
having a base of polyethylene glycols or polyethylene oxides and 8 magnesium
chloride, acidified with P2O5)

The polymeric electrolyte obtained according to the foregoing Example B.6.4 is treated with 8 wt% of P205. The time required for obtaining a polymeric electrolyte by means of stirring and complete dissolution of the P2Os is approximately 4 hours. The addition of P2O5 increases the viscosity of the polymer. BJ - Example of preparation of the polymeric electrolyte 12 reinforced with glass fibres
The liquid polymeric electrolyte or solid polymeric electrolyte in the molten state is used for impregnating a glass-fibre fabric. In this way, a thin layer of polymeric electrolyte is obtained which is reinforced with glass fibres. C - Examples of prototypes produced
Practical tests carried out on prototypes revealed that the task and purposes set had been achieved.
In particular, in one first case (single-element button battery with polymeric electrolyte reinforced with a porous paper filter), an anodic disk (anode 10) made of sintered metallic magnesium and having a diameter of 8 mm was interfaced with a film of polymeric electrolyte PEG 400 (MgCl2)x reinforced with a paper disk having the same diameter, after prior heating of the two compounds. On top of the polymeric-electrolyte film was laid a composite cathodic film (cathode 11) having a base of intercalation material consisting of metal oxides with graphite in liquid suspension subsequently dried, prepared according to the previous examples. The element thus obtained was housed on a system consisting of two current collectors 13. A few instants after assembly, this prototype revealed a voltage of approximately 0.8 V. Within approximately 5-6 hours, the voltage of the battery prototype increased until it reached approximately 1.8 V. After a few rechargings were carried out at a constant current of between 5 and 150 |iA, the prototype presented a threshold voltage between 2 and 3 V. After discharge, the voltage returned to 1.8 V.
In a second case (single-element button battery with polymeric electrolyte reinforced with glass fibre), the anode 10 and cathode 11 were prepared according to the same procedures as for the first prototype. In the present case, as reinforcement for the polymeric electrolyte 12, glass fibre having a thickness of 0.02 mm was used. The characteristics of this prototype were the same as for

those of the first prototype, but the reversibility was considerably superior. In a third case (single-element button battery with polymeric electrolyte acidified with P205 and reinforced with glass fibres), the anode 10 and cathode 11 were prepared following the same procedures as for the first prototype. Acidification of the polymeric electrolyte 12 by means of P2O5 enabled a voltage of approximately 2.2 V to be obtained, together with excellent reversibility, a high specific energy density, and a considerable charge capacity.
From the examples given above there clearly emerge the advantages that may be obtained using magnesium for the production of the batteries that form the object of the present invention. In addition, when compared to lithium, magnesium, which is a very light element, presents characteristics of better workability, together with a good reactivity and oxide-reducing voltage. The possibility for magnesium to exchange two electrons may enable an efficiency of 100%, and, given the same volumes, magnesium may reach 80% more in terms of charge and 45% more in terms of energy as compared to lithium.
The systems developed according to the technology described herein enable, in fact, excellent technical performance to be achieved, allied to the advantage of a reduction in production costs and to the practically total absence of environmental impact, given that the component materials are all non-polluting and that magnesium is a safe element as demonstrated by its medical and clinical uses. The invention thus conceived may undergo numerous modifications and variations, and, without departing from the scope of the inventive idea of the present invention, it is possible for a person skilled in the branch to make, to the primary (non-rechargeable) and secondary (rechargeable) batteries that form the object of the present invention, all the modifications and improvements resulting from normal technical know-how and experience in the sector, as well as from the natural evolution of the state of the art.

WE CLAIM:
1. A primary (non-rechargeable) and secondary (rechargeable) batteries, of the type
comprising at least one anode, at least one cathode, at least one electrolyte set between
anode and cathode, and current collectors, said batteries being characterized in that at
least:
-the anode contains magnesium in the various states of oxidation Mgn+ (n+== °, 1+' ), optionally combined with metallic magnesium
-the electrolyte contains as ionic species magnesium chlorides in 5 form having lattice energy lower than 500 kcal/mol in solvents capable of producing electrolytes having good ionic conductivity, and of solvating said species.
2. The batteries according to Claim 1, wherein also the cathode contains magnesium.
3. The batteries according to Claim 1, wherein the anode comprises metallic
magnesium laminated or sintered.
4. The batteries according to Claim 1 wherein the anode comprises magnesium on a substrate of highly conductive organic or inorganic material chosen from among metals, oxides, alloys or fabrics thereof, carbon fibre and carbon fibre fabrics, graphite, or graphite-based composites.
5. The batteries according to Claim 1, wherein the anode comprises magnesium intercalated or embedded in highly conductive organic or inorganic materials, which intercalate or embed, in their own matrices, magnesium crystallites of reduced

dimensions or magnesium monocrystals, chosen from among oxides, sulphides, phosphates or phosphides of transition metals, alkaline metals, and alkaline-earth metals, as well as non-metal compounds or having a base of carbons with a highly crystalline or irregular structure or carbon-based polymers.
6. The batteries according Claims 3 and 5 wherein the anode is oxidised with
oxidising agents chosen from among oxygen gas, hydrogen peroxide, or organic
peroxides.
7. The batteries according Claims from 3 to 6 wherein the anode is stabilized by treatment with alkoxides chosen from among tetra-alkoxy titanium, tetra-alkoxy silanes, trialkoxy aluminium, tetra-alkoxy zirconium, or magnesium dialkoxide.
8. The batteries according to Claim 1, wherein the electrolyte comprises as solvent any liquid or polymeric organic solvent material having polar groups or heteroatoms chosen from oxygen, nitrogen, silicon and phosporus which co-ordinate and dissociate the magnesium chlorides in 5 form.
9. The batteries according to Claim 8 wherein the electrolyte comprises as polymeric solvent polyalkylene glycols and or polyalkylene oxides.
10. The batteries according Claims 8 and 9, wherein the electrolyte is acidified with
compounds having a base of phosphorus, polyphosphates, P2O5, or orthophosphoric
acid.

11. The batteries according to Claims 8 and 9, wherein the electrolyte is alkalinized with compounds being a base or nitrogen such as amines and ammonia, or with basic derivatives of sulphur or phosphorus.
12. The batteries according to Claims 1 and 2 wherein the cathode comprises magnesium on a substrate of highly conductive organic or inorganic materials chosen from among metals, oxides, alloys or fabrics made of the same, carbon fibre and carbon-fibre fabrics, graphite or graphite-based composites.
13. The batteries according to Claims 1 and 2, wherein the cathode comprises magnesium in organic or inorganic materials that intercalate or embed magnesium chosen from among oxides, sulphides, phosphates or phosphides of transition metals, alkaline metals, and alkaline-earth metals, as well as non-metal compounds or having a base of carbons with a highly crystalline or irregular structure or carbon-based polymers.
14. The batteries according Claims 12 and 13 wherein the cathode is oxidised with oxidising agents chosen from among oxygen gas, hydrogen peroxide, or organic peroxides.
15. The batteries according Claims 12 and 13 wherein the cathode is prepared with electrochemically active material partially oxidised with oxidising agents chosen from among oxygen gas, hydrogen peroxide, or organic peroxides.

16. The method for the production of batteries according to Claim 1, wherein it
envisages of the following step:
-preparation of an anode wherein it comprises magnesium in the various states of oxidation Mgn+(n+== °' 1+' 2+), optionally combined with metallic Mg, said anode having a base of metallic magnesium, or else of magnesium on a substrate of highly conductive inorganic or organic materials, or in inorganic or organic materials for intercalation or embedding of the magnesium and
-preparation of an electrolyte wherein it comprises as ionic species magnesium chlorides in 8 form in solvents that are capable of producing electrolytes having good ionic conductivity and of solvating said species and optionally
-preparation of a cathode wherein it comprises species of magnesium having a substrate of highly conductive inorganic or organic materials or in inorganic or organic materials for intercalation or embedding of the magnesium.
17. The method for the production of batteries according to Claim 16, wherein the anode is prepared from laminated or sintered metallic magnesium.
18. The method for the production of batteries according to Claim 16, wherein the anode having a base of magnesium on a substrate is prepared by chemical or thermal vapour deposition, or electrolytic deposition, or electrochemical deposition of the magnesium on organic or inorganic materials chosen from among metals, oxides, alloys or fabrics made of the same, carbon fibre carbon fibre fabrics, graphite, or graphite-based composites.

19. The method for the production of batteries according to Claim 16, wherein the anode with a base of magnesium in intercalation or embedding material is prepared by (i) homogenization and pelletization of a mixture of an intercalation or embedding material, ground up to complete structural disorder, and magnesium carbonates or oxides brought up to a temperature of between 100 and 400°C for a period of time of between 1 and 3 hours, (ii) then heating up to temperatures of between 800 and 1200°C in an inert atmosphere, (iii) and finally keeping at this temperature for 1-5 days in vacuum conditions.
20. The method for the production of batteries according to Claim 16, wherein the anode with a base of magnesium in intercalation or embedding material is prepared by solvent-casting of a solvent such as benzene, toluene, N-N dimethyl acetamide, dimethyl formamide, or tetrahydrofuran, containing, in a homogeneous way, a mixture of polymers chosen from among polyethylene, polyvinyl chloride, polyacrylamide or polyacrylonitrile, or similar polymers, and the intercalation or embedding material chosen, previously extended up to complete homogenization with magnesium.
21. The method for the production of batteries according to Claim 16, wherein the anode with a base of magnesium in intercalation or embedding material for intercalating or embedding magnesium is prepared by plasma spraying or sputtering of the magnesium into the intercalation or embedding material chosen.

22. The method for the production of batteries according to any one of Claims 16-21, wherein the anode is oxidised with oxidising agents chosen from among oxygen gas, hydrogen peroxide, or organic peroxides.
23. The method for the production of batteries according to any one of Claims 16-22, wherein the anode is stabilized by treatment with alkoxides chosen from among tetra-alkoxy titanium, tetra-alkoxy silanes, trialkoxy aluminium, tetra-alkoxy zirconium, or magnesium dialkoxide.
24. The method for the production of batteries according to Claim 16, wherein the electrolyte is prepared by direct dissolution of the 8-magnesium chlorides in the liquid solvent or molten polymer.
25. The method for the production of batteries according to Claim 16, wherein the electrolyte is prepared by solvent-casting of the common solvent of the polymer and of the 8- magnesium chlorides.
26. The method for the production of batteries according to Claim 16, wherein the electrolyte is prepared by dissolution of the 5-magnesium chlorides in one or more monomers and by subsequent polymerization.
27. The method for the production of batteries according to Claim 16, wherein the cathode having a base of magnesium on a substrate is prepared by chemical or thermal vapour deposition, or electrolytic deposition, or electrochemical deposition of the magnesium on organic or inorganic materials chosen from among metals, oxides,

alloys, or fabrics made of the same, carbon fibre, carbon fibre fabrics, graphite, or
graphite-based composites.
28. The method for the production of batteries according to Claim 16, wherein the
cathode with a base of magnesium in intercalation or embedding material is prepared
by:
(i) homogenization and pelletization of a mixture of an intercalation or embedding material, ground up to complete structural disorder, and magnesium carbonates or oxides brought up to a temperature of between 100 and 400°C for a period of time of between 1 and 3 hours, (ii) then heating up to temperatures of between 800 and 1200°C in an inert atmosphere, (iii) and finally keeping at this temperature for 1-5 days in vacuum conditions.
29. The method for the production of batteries according to Claim 16, wherein the cathode with a base of magnesium in intercalation or embedding material is prepared by solvent-casting of a solvent such as benzene, toluene, N-N dimethyl acetamide, dimethyl formamide, or tetrahydrofuran, containing, in a homogeneous way, a mixture of polymers chosen from among polyethylene, polyvinyl chloride, polyacrylamide or polyacrylonitrile, or similar polymers, and the intercalation or embedding material previously extended up to complete homogenization with magnesium.
30. The method for the production of batteries according to Claim 16, wherein the cathode with a base of magnesium in intercalation or embedding material is prepared by plasma spraying or sputtering of the magnesium into the intercalation or embedding material chosen.

31. The method for the production of batteries according to any one of Claims 27-30,
wherein the magnesium of the cathode is oxidized with oxidising agents chosen
among from oxygen gas, hydrogen peroxide, or organic peroxides.
32. The method for the production of batteries according to any one of Claims 27-30,
wherein the cathode is prepared with electrochemically active materials previously
partially oxidized with oxidising agents chosen among from oxygen gas, hydrogen
peroxide, or organic peroxides.
33 The method for setting magnesium batteries according to any one of preceding claims, wherein at least one anode, at least one cathode, at least one electrolyte, current collectors and optionally dielectric spacers are put in contact between one another, setting the electrolyte between anode and cathode at temperatures of between room temperature and approximately 150°C.

Documents:

in-pct-2002-0206-che claims-duplicate.pdf

in-pct-2002-0206-che description (complete)-duplicate.pdf

in-pct-2002-0206-che drawings-duplicate.pdf

in-pct-2002-206-che-abstract.pdf

in-pct-2002-206-che-claims.pdf

in-pct-2002-206-che-correspondance other.pdf

in-pct-2002-206-che-correspondance po.pdf

in-pct-2002-206-che-description complete .pdf

in-pct-2002-206-che-drawings.pdf

in-pct-2002-206-che-form 1.pdf

in-pct-2002-206-che-form 19.pdf

in-pct-2002-206-che-form 3.pdf

in-pct-2002-206-che-form 5.pdf

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Patent Number

222307

Indian Patent Application Number

IN/PCT/2002/206/CHE

PG Journal Number

47/2008

Publication Date

21-Nov-2008

Grant Date

05-Aug-2008

Date of Filing

06-Feb-2002

Name of Patentee

UNIVERSITA' DEGLI STUDI DI PADOVA

Applicant Address

VIA VIII FEBARIO 1848, N. 2, I-35122 PADOVA,

Inventors:

#	Inventor's Name	Inventor's Address
1	FAURI, MAURIZIO	VIA MONTE PASUBIO, 19, I-35010 VIGONZA,
2	DI NOTO, VITO	VIA QUERINI 40, I-35135 ALTICHIERO,

PCT International Classification Number

H01M 10/40

PCT International Application Number

PCT/EP00/07221

PCT International Filing date

2000-07-27

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	PD99A000179	1999-07-29	Italy