Title of Invention	AN IMPROVED PROCESS FOR THE PREPARATION OF NANO-COMPOSITE CATHODE MATERIALS FOR HIGH ENERGY DENSITY RECHARGABLE LITHIUM BATTERIES
Abstract	A process for the preparation of nanocomposite cathode material which comprises preparing a mixture of a polymer and an inorganic salt of a transition metal selected from D-block of the periodic table such as herein described, at a ratio 1:1, in water/organic solvent, drying the said mixture at a temperature ranging between 100 to 250°C, palletizing the dried mixture by conventional methods, heating the said pellets to a temperature ranging between 400 to 800°C in inert atmosphere and finally sintering the resultant by known methods to obtain nano-composite cathode material.

Title of Invention

AN IMPROVED PROCESS FOR THE PREPARATION OF NANO-COMPOSITE CATHODE MATERIALS FOR HIGH ENERGY DENSITY RECHARGABLE LITHIUM BATTERIES

Abstract

A process for the preparation of nanocomposite cathode material which comprises preparing a mixture of a polymer and an inorganic salt of a transition metal selected from D-block of the periodic table such as herein described, at a ratio 1:1, in water/organic solvent, drying the said mixture at a temperature ranging between 100 to 250°C, palletizing the dried mixture by conventional methods, heating the said pellets to a temperature ranging between 400 to 800°C in inert atmosphere and finally sintering the resultant by known methods to obtain nano-composite cathode material.

Full Text	This invention relates to an improved process for the preparation of nanocomposite cathode material. More particularly this invention relates to an improved process for the preparation of nanocomposite cathode material useful for high energy density rechargeable Lithium batteries. The nanocomposite cathode prepared by the present invention are nanocomposite of oxides and sulphides of transition metals uniformly dispersed in a highly conducting carbonaceous matrix, which prove to be very useful in high energy density non-aqueous Lithium rechargeable batteries. More specifically the present invention relates to an improved process for making high energy density Lithium rechargeable battery cathodes, based on nano-composites prepared by decomposing a mixture of an aromatic polymer and transition metal salts with or without boron or phosphorous compounds. Thereby a conducting carbonaceous composite partly amorphous and partly crystalline can be obtained capable of delivering high energy and power density after coupling with a metallic Lithium electrode anode in an electrolyte solution using Lithium salts and specific solvents. Lithium rechargeable batteries are a promising class of high energy-density power sources; specially used for several portable electronic devices like laptop computers, cellular phones, electronic watches, calculators, cameras and metal oxide semiconductor memories where, light weight and small size are crucial for applications along with other advantages of high energy and power density. High energy-density Lithium rechargeable batteries are also useful for the space and defense programs, for electric vehicles and for other consumer markets such as power sources for human implantable devices. Lithium metal as an anode has low molecular weight, high standard electrode potential (3.045V), high charge density (3860Ah/Kg) and hence is one of the most attractive negative electrode material for high energy density Lithium rechargeable batteries although limitations exist due to its high reactivity, poor reversibility and the need for handling in an inert atmosphere. Some of these limitations can be partly removed by using alternatives such as Li alloys (Li-Al, Li-Sn), Li-ion insertion anodes and more recently new compositions like [Science 276, 1395-1397 (1997)] amorphous Sn based composites or even phases such as LiCe. Some of these are found to be very useful as anodes to replace Li metal, but development of a suitable rechargeable cathode to match the energy density still remains a challenge. Different types of Lithium rechargeable battery cathodes are commercially available at present, but their performance does not meet all the goals required for the development of novel batteries. The main emphasis is on lightweight or low-density cathode material, longer life time and room temperature operation with fast charging besides the low material cost. Several approaches are being pursued in all over the world in this direction, including the development of different types of compounds and mixtures for the secondary Lithium battery cathode. The oxides of transition metal such as LiCoO2, LiMn2O4, LiFeO2, LiNiO2, V2O5, Cr2O5, MnO2, MoO2, WO2, as well as the chalcogenides like TiS2, MoS2, FeS2 have been tried by several investigators. Some of these compounds possessing either a layer or tunnel structure are found to be very useful but performance deterioration is common with increasing the cycle life. One approach (JP No. 31408 dated 2nd Feb. 1996) involves the preparation of compounds of the type LixA1-yMyO2 where, A indicates Mn, Co and or Ni and the symbol M includes Mg, Ca etc (where, 0.05 X 1.1, 0 Y0.5) and this active material is mixed with an adhesive polymer and acetylene black to make the positive electrode paste. Such positive electrodes when used in non-aqueous Lithium secondary cells are found to give no deterioration upon storage and more importantly, a high value of discharge capacity. Similarly superior reliability characteristics over a long duration of time (JP No. 9-7602 dated 10th Jan 1997) was observed for LixMoO2 active material pasted on a Al substrate grid with a 3 micron coating of metallic chromium. Other approaches being tried to include use of different types of intercalated compounds, conducting polymers, amorphous Mn-based oxyiodide compound [Nature 390, 265-267 (1997)] etc for enhancing the performance of the cathode in Lithium rechargeable battery. However, there are also several drawbacks with the prior art cathodes. Most of these cathodes do not possess high capacity during cycling at moderate current densities and for widespread applications their poor cycle life needs to be improved significantly. Prior art cathode material is based on a bulk property which is communicated through the surface in any interface creates a problem of surface degradation during the cycling so that surface becomes quite different from the bulk which in turn gives small dependent product life time. In addition the energy density, cycle life and operating current density of the prior art cathodes are limited due to various degradation modes such as grain growth during cycling, open circuit stand, self discharge due to parasitic corrosion reaction and large ohmic drop due to formation of insulating phases. During the fabrication stage of the prior art cathodes, external additives like graphite or acetylene black are used which gives the poor mechanical strength, high ohmic drop and poor utilization efficiency due to poor bonding between the graphitic carbon and metal oxides. On the contrary, cathodes prepared by the process of present invention does not need external additives like graphite or acetylene black, as there is uniform dispersion of transition metal oxide/sulphide nano-particles in highly conducting carbonaceous matrix, which in turn gives good bonding between graphitic carbon and metal oxides/sulphides and high mechanical strength to cathodes. In the case of nano-composites cathode there is no bulk and hence there is no question of a surface degradation. Therefore, several transition metal oxides/sulphides in situ generated in a highly conducting carbon matrix can be used to avoid the limitations of conventional cathodes such as FeS2, V2O5, TiF2, MoO2, etc. The graphite or graphite like carbon formed during this process provides the carbonaceous environment. By changing the preparation conditions the conductivity of the carbonaceous matrix may be changed from lO-8Ώlcm"1 to 10+2 Ώ^cm"1 and the nanocomposite cathode material obtained may be in the form of the black powder or a sintered pellet. The high-conductivity carbonaceous matrix may be obtained from any one or combination of two or more aromatic polymers, having the decomposition point in the temperature range of 200-300°C in the presence of at least one benzene ring in the monomer unit and presence of one or more elements including S, N, Se and Te. WO2, MoO2, VO2 etc. are the conducting oxides, TiO2, NiO, CoO etc. are the insulating oxides and ZnS, CdS are the semiconducting sulphides of the d-Block elements. It has been observed that the nanocomposites of transition metal oxides/sulphides dispersed in the carbonaceous matrix provide better cathodes for rechargeable Lithium cell removing the drawbacks in the prior art cathodes. The object of the present invention is to provide a process for the preparation of nanocomposite cathode materials of metal oxides/sulphides uniformly dispersed in a conducting carbonaceous matrix useful for high energy density rechargeable Lithium batteries. Another object is to provide a process for the preparation of nano-compsite cathode of the oxides and sulphides of the transition metals viz. Cd, Zn, Mo, Fe, V, Sn, W, Ni, Co et. In highly conducting carbonaceous matrix for getting the high energy density with good reversibility for rechargeable Lithium battery, more specifically it is the process for dispersing the nano-dimensional particles of the metal oxides/sulphides uniformly in a highly conducting environment, mainly in a carbonaceous environment for obtaining nano-composite cathode. Accordingly, the present invention provides a A process for the preparation of nanocomposite cathode material which comprises preparing a mixture of a polymer and an inorganic salt of a transition metal selected from D-block of the periodic table such as herein described, at a ratio 1:1, in water/organic solvent, drying the said mixture at a temperature ranging between 100 to 250°C, palletizing the dried mixture by conventional methods, heating the said pellets to a temperature ranging between 400 to 800°C in inert atmosphere and finally sintering the resultant by known methods to obtain nano-composite cathode material. In one of the embodiments of the present invention the polymer used may be selected from poly-l,4-phenylene sulphide, poly-2-vintyl pyridine, poly-phenylene oxide, poly-phenylene selenide, poly-phenylene telluride and poly-acrylonitrile. In another embodiment of the present invention the inorganic salt of metal used may be selected from one or more of the group consisting of tarterates, oxalates, halides, nitrates, citrates and ammonium salts of one or more metals selected from the group consisting of V, Mo, Cd, y, Ni, W, Ba, Ti and Sn, preferably ammonium molybdate and vandate. In another embodiment the appropriate solvent used may be water or organic solvents such as acetone, ethanol, butanol, benzene and isopropanol. In yet another embodiment the compaction pressure applied may be in the range of 4000 to 10,000psi; preferably 5000 to 5500psi. In still another embodiment, the inert atmosphere may be created using nitrogen, argon and helium. In a feature of the present invention the product could be moulded in various shapes and forms to suit the physical parameters of the batteries in which the said product is intended to be used. The above pellet when immersed in an electrolyte solution of Lithium salt like LiC104, LiAsF6, LiPF6, Lil, LiBr, LiCl etc. and coupled with an anode selected from Li metal, Li- Al or Li-Sn alloy, LiC6 etc. shows an open-circuit voltage ranging from 2.9 to 4V. When charge-discharge cycling was conducted at either constant current or constant potential mode different energy and power density values were observed depending on the composition. The capacity values were found to be invariant with respect to cycle number and some typical values corresponding to a galvanostatic discharge at 1 mAcm'2 are indicated in the accompanying Table. Table 1. Capacity/Energy density (Formula Removed) 5 to 8 Present work The process of the present invention is explained in details in the following examples, which are given by way of illustration only and therefore should not be construed to limit the scope of the present invention in any manner. EXAMPLE - 1 1.6381gm of ammonium molybdate tetrahydrate (AM) and 1.0861gm of ammonium metavandate (AV) was mixed with 2gm of poly-phenylene sulphide (PPS) in the molar ratio of 0.5:0.5:1 in a pestle and mortar using water as solvent. Dry mixture was then pressed into pellets of thickness 2mm and diameter 8mm by the application of a compaction load of 5OOOpsi. These pellets were then heated in nitrogen environment at temperature 550°C for two hours followed by slow cooling to room temperature. The residual product obtained at 550°C was again repelletised and heated in nitrogen atmosphere at 800°C for two hours followed by slow cooling to room temperature. Residual product obtained at 800°C was then used for fabricating cathodes. This nano-composite was mixed with PTFE binder (in the ratio of 95:5 by weight) and was then pressed on nickel mesh of thickness 0.05mm and area 1.6 cm2 by using the compaction load of 10,000psi. 1M solution of LiClO4 in tetrahydrofuran (THF) was used for the electrolyte and a constant value of 0.65mA/cm2 as the current density was used for the charge-discharge studies. The open circuit voltage was observed to be 3.201V and the energy density obtained from the discharge capacity was 120 Wh/kg. EXAMPLE - 2 1.6324gm of ammonium molybdate tetrahydrate (AM) and 0.1143gm of boric acid (BA) was mixed with 1gm of (PPS) poly-phenylene sulphide in the molar ratio of 1:0.2:1 in a pestle and mortar using water as solvent. Dry mixture was then pressed into pellets of thickness 2mm and diameter 8mm by the application of a compaction load of 5OOOpsi. These pellets were then heated in nitrogen environment at temperature 410°C for two hours followed by slow cooling to room temperature. The residual product obtained at 410°C was again repelletised and heated in nitrogen atmosphere at 550°C for two hours followed by slow cooling to room temperature. Residual product obtained at 550°C was then used for fabricating cathodes. This nano-composite was mixed with PTFE binder (in the ratio of 95:5 by weight) and then pressed on nickel mesh of thickness 0.05mm and area 1.65cm2 by using the compaction load of 10,000psi. 1M solution of LiAsF6 in 1:1 mixture of propylene carbonate and tetrahydrofuran was used for the electrolyte and a constant value 0.166mA/cm as the current density was used for the charge-discharge studies. The open circuit voltage was observed to be 2.8V and, the energy density obtained from the discharge capacity was 96Wh/kg. EXAMPLE - 3 1.6324gm of ammonium molybdate tetrahydrate (AM) was mixed with 1gm of poly-phenylene sulphide (PPS) in the molar ratio of 1:1 in a pestle and mortar using water as solvent. Dry mixture was then pressed into pellets of thickness 2mm and diameter 8mm by the application of a compaction load of 5OOOpsi. These pellets were then heated in nitrogen environment at temperature 550°C for two hours followed by slow cooling to room temperature. The residual product obtained at 550°C was again repelletised and heated in nitrogen atmosphere at 800°C for two hours followed by slow cooling to room temperature. Residual product obtained at 800°C was then used for fabricating cathode. This nano-composite was mixed with PTFE binder (in the ratio of 95:5 by weight) and was then pressed on nickel mesh of thickness 0.05mm and area 0.8cm2 by using the compaction load of lOOOOpsi. 1M solution of LiClO4 in propylene carbonate was used for electrolyte. 0.65 mA/cm current density was used for charge-discharge operation. The open circuit voltage was observed to be 2.902V and energy density obtained from discharge capacity was 217 Wh/kg. EXAMPLE-4 1.6786gm of ammonium molybdate tetrahydrate (AM) was mixed with Igm of poly-2-vinylpyridine (PVP) in the molar ratio of 1:1 in a pestle and mortar using water as solvent. Dry mixture was then pressed into pellets of thickness 2mm and 8 mm diameter by the application of a load of 5OOOpsi. These pellets were then heated at temperature 410°C and then at 550°C for two hours followed by slow cooling to room temperature. Residual product material was then mixed with the PTFE binder in the ratio of 95:5 by weight percent to make cathode electrode. To make the cathode electrode this mixture was then pressed on nickel mesh of thickness 0.05mm and 1cm2 area by using the load of lOOOOpsi. 1M solution of LiPF6 in propylene carbonate was used for electrolyte. 0.25 mA/cm2 current density was used for charge-discharge studies. The open circuit voltage was observed to be 3.01V and energy density obtained from discharge capacity was 115.6 Wh/kg. We Claim: 1. A process for the preparation of nanocomposite cathode material which comprises preparing a mixture of a polymer and an inorganic salt of a transition metal selected from D-block of the periodic table such as herein described, at a ratio 1:1, in water/organic solvent, drying the said mixture at a temperature ranging between 100 to 250°C, palletizing the dried mixture by conventional methods, heating the said pellets to a temperature ranging between 400 to 800°C in inert atmosphere and finally sintering the resultant by known methods to obtain nano-composite cathode material. 2. A process as claimed in claim 1 wherein, the polymer used is selected from poly-1,4- phenylene sulphide, poly-2-vinyl pyridine, poly-phenylene oxide, poly-phenylene selenide, poly-phenylene telluride and poly-acrylonitrile. 3. A process as claimed n claim 1 wherein, the inorganic salt of metal is selected from one or more of the group consisting of tartrates, oxalates, halides, nitrates, citrates and ammonium salts of one or more metals selected from the group consisting of V, Mo, Cd, Y, Ni, W, Ba, Ti and Sn, preferably ammonium molybadate and vandate. 4. A process claimed in claim 1, wherein the solvent used is water or organic solvents such as acetone, butanol, ethanol, benzene, isopropanol. 5. A process as claimed in claim 1, wherein the palletizing is done by compaction pressure applied is in the range of 4000 to 10000 psi; preferably 5000 to 5500 psi. 6. A process as claimed in claim 1, wherein inert atmosphere is created using nitrogen, argon and helium. 7. A process for the preparation of nanocomposite cathode material described herein before with reference to examples.

Full Text

This invention relates to an improved process for the preparation of nanocomposite cathode material. More particularly this invention relates to an improved process for the preparation of nanocomposite cathode material useful for high energy density rechargeable Lithium batteries. The nanocomposite cathode prepared by the present invention are nanocomposite of oxides and sulphides of transition metals uniformly dispersed in a highly conducting carbonaceous matrix, which prove to be very useful in high energy density non-aqueous Lithium rechargeable batteries. More specifically the present invention relates to an improved process for making high energy density Lithium rechargeable battery cathodes, based on nano-composites prepared by decomposing a mixture of an aromatic polymer and transition metal salts with or without boron or phosphorous compounds. Thereby a conducting carbonaceous composite partly amorphous and partly crystalline can be obtained capable of delivering high energy and power density after coupling with a metallic Lithium electrode anode in an electrolyte solution using Lithium salts and specific solvents.
Lithium rechargeable batteries are a promising class of high energy-density power sources; specially used for several portable electronic devices like laptop computers, cellular phones, electronic watches, calculators, cameras and metal oxide semiconductor memories where, light weight and small size are crucial for applications along with other advantages of high energy and power density. High energy-density Lithium rechargeable batteries are also useful for the space and defense programs, for electric vehicles and for other consumer markets such as power sources for human implantable devices. Lithium metal as an anode has low molecular weight, high standard electrode potential (3.045V), high charge density (3860Ah/Kg) and hence is one of the most attractive

negative electrode material for high energy density Lithium rechargeable batteries although limitations exist due to its high reactivity, poor reversibility and the need for handling in an inert atmosphere. Some of these limitations can be partly removed by using alternatives such as Li alloys (Li-Al, Li-Sn), Li-ion insertion anodes and more recently new compositions like [Science 276, 1395-1397 (1997)] amorphous Sn based composites or even phases such as LiCe. Some of these are found to be very useful as anodes to replace Li metal, but development of a suitable rechargeable cathode to match the energy density still remains a challenge.
Different types of Lithium rechargeable battery cathodes are commercially available at present, but their performance does not meet all the goals required for the development of novel batteries. The main emphasis is on lightweight or low-density cathode material, longer life time and room temperature operation with fast charging besides the low material cost.
Several approaches are being pursued in all over the world in this direction, including the development of different types of compounds and mixtures for the secondary Lithium battery cathode. The oxides of transition metal such as LiCoO2, LiMn2O4, LiFeO2, LiNiO2, V2O5, Cr2O5, MnO2, MoO2, WO2, as well as the chalcogenides like TiS2, MoS2, FeS2 have been tried by several investigators. Some of these compounds possessing either a layer or tunnel structure are found to be very useful but performance deterioration is common with increasing the cycle life. One approach (JP No. 31408 dated 2nd Feb. 1996) involves the preparation of compounds of the type LixA1-yMyO2 where, A indicates Mn, Co and or Ni and the symbol M includes Mg, Ca etc (where, 0.05 X 1.1, 0 Y0.5) and this active material is mixed with an adhesive polymer and acetylene black to

make the positive electrode paste. Such positive electrodes when used in non-aqueous Lithium secondary cells are found to give no deterioration upon storage and more importantly, a high value of discharge capacity. Similarly superior reliability characteristics over a long duration of time (JP No. 9-7602 dated 10th Jan 1997) was observed for LixMoO2 active material pasted on a Al substrate grid with a 3 micron coating of metallic chromium. Other approaches being tried to include use of different types of intercalated compounds, conducting polymers, amorphous Mn-based oxyiodide compound [Nature 390, 265-267 (1997)] etc for enhancing the performance of the cathode in Lithium rechargeable battery.
However, there are also several drawbacks with the prior art cathodes. Most of these cathodes do not possess high capacity during cycling at moderate current densities and for widespread applications their poor cycle life needs to be improved significantly. Prior art cathode material is based on a bulk property which is communicated through the surface in any interface creates a problem of surface degradation during the cycling so that surface becomes quite different from the bulk which in turn gives small dependent product life time. In addition the energy density, cycle life and operating current density of the prior art cathodes are limited due to various degradation modes such as grain growth during cycling, open circuit stand, self discharge due to parasitic corrosion reaction and large ohmic drop due to formation of insulating phases. During the fabrication stage of the prior art cathodes, external additives like graphite or acetylene black are used which gives the poor mechanical strength, high ohmic drop and poor utilization efficiency due to poor bonding between the graphitic carbon and metal oxides. On the contrary, cathodes prepared by the process of present invention does not need
external additives like graphite or acetylene black, as there is uniform dispersion of transition metal oxide/sulphide nano-particles in highly conducting carbonaceous matrix, which in turn gives good bonding between graphitic carbon and metal oxides/sulphides and high mechanical strength to cathodes. In the case of nano-composites cathode there is no bulk and hence there is no question of a surface degradation. Therefore, several transition metal oxides/sulphides in situ generated in a highly conducting carbon matrix can be used to avoid the limitations of conventional cathodes such as FeS2, V2O5, TiF2, MoO2, etc.
The graphite or graphite like carbon formed during this process provides the carbonaceous environment. By changing the preparation conditions the conductivity of the carbonaceous matrix may be changed from lO-8Ώlcm"1 to 10+2 Ώ^cm"1 and the nanocomposite cathode material obtained may be in the form of the black powder or a sintered pellet. The high-conductivity carbonaceous matrix may be obtained from any one or combination of two or more aromatic polymers, having the decomposition point in the temperature range of 200-300°C in the presence of at least one benzene ring in the monomer unit and presence of one or more elements including S, N, Se and Te. WO2, MoO2, VO2 etc. are the conducting oxides, TiO2, NiO, CoO etc. are the insulating oxides and ZnS, CdS are the semiconducting sulphides of the d-Block elements. It has been observed that the nanocomposites of transition metal oxides/sulphides dispersed in the carbonaceous matrix provide better cathodes for rechargeable Lithium cell removing the drawbacks in the prior art cathodes.
The object of the present invention is to provide a process for the preparation of nanocomposite cathode materials of metal oxides/sulphides uniformly dispersed in a

conducting carbonaceous matrix useful for high energy density rechargeable Lithium batteries.
Another object is to provide a process for the preparation of nano-compsite cathode of the oxides and sulphides of the transition metals viz. Cd, Zn, Mo, Fe, V, Sn, W, Ni, Co et. In highly conducting carbonaceous matrix for getting the high energy density with good reversibility for rechargeable Lithium battery, more specifically it is the process for dispersing the nano-dimensional particles of the metal oxides/sulphides uniformly in a highly conducting environment, mainly in a carbonaceous environment for obtaining nano-composite cathode.
Accordingly, the present invention provides a A process for the preparation of nanocomposite cathode material which comprises preparing a mixture of a polymer and an inorganic salt of a transition metal selected from D-block of the periodic table such as herein described, at a ratio 1:1, in water/organic solvent, drying the said mixture at a temperature ranging between 100 to 250°C, palletizing the dried mixture by conventional methods, heating the said pellets to a temperature ranging between 400 to 800°C in inert atmosphere and finally sintering the resultant by known methods to obtain nano-composite cathode material.
In one of the embodiments of the present invention the polymer used may be selected from poly-l,4-phenylene sulphide, poly-2-vintyl pyridine, poly-phenylene oxide, poly-phenylene selenide, poly-phenylene telluride and poly-acrylonitrile.
In another embodiment of the present invention the inorganic salt of metal used may be selected from one or more of the group consisting of tarterates, oxalates, halides, nitrates, citrates and ammonium salts of one or more metals selected from the group consisting of V, Mo, Cd, y, Ni, W, Ba, Ti and Sn, preferably ammonium molybdate and vandate.

In another embodiment the appropriate solvent used may be water or organic solvents
such as acetone, ethanol, butanol, benzene and isopropanol.
In yet another embodiment the compaction pressure applied may be in the range of 4000
to 10,000psi; preferably 5000 to 5500psi.
In still another embodiment, the inert atmosphere may be created using nitrogen, argon
and helium.
In a feature of the present invention the product could be moulded in various shapes and
forms to suit the physical parameters of the batteries in which the said product is intended
to be used.
The above pellet when immersed in an electrolyte solution of Lithium salt like LiC104,
LiAsF6, LiPF6, Lil, LiBr, LiCl etc. and coupled with an anode selected from Li metal, Li-
Al or Li-Sn alloy, LiC6 etc. shows an open-circuit voltage ranging from 2.9 to 4V. When
charge-discharge cycling was conducted at either constant current or constant potential
mode different energy and power density values were observed depending on the
composition. The capacity values were found to be invariant with respect to cycle number
and some typical values corresponding to a galvanostatic discharge at 1 mAcm'2 are
indicated in the accompanying Table.
Table 1.

Capacity/Energy density
(Formula Removed)

5 to 8 Present work

The process of the present invention is explained in details in the following examples, which are given by way of illustration only and therefore should not be construed to limit the scope of the present invention in any manner.
EXAMPLE - 1
1.6381gm of ammonium molybdate tetrahydrate (AM) and 1.0861gm of ammonium metavandate (AV) was mixed with 2gm of poly-phenylene sulphide (PPS) in the molar ratio of 0.5:0.5:1 in a pestle and mortar using water as solvent. Dry mixture was then pressed into pellets of thickness 2mm and diameter 8mm by the application of a compaction load of 5OOOpsi. These pellets were then heated in nitrogen environment at temperature 550°C for two hours followed by slow cooling to room temperature. The residual product obtained at 550°C was again repelletised and heated in nitrogen atmosphere at 800°C for two hours followed by slow cooling to room temperature. Residual product obtained at 800°C was then used for fabricating cathodes. This nano-composite was mixed with PTFE binder (in the ratio of 95:5 by weight) and was then pressed on nickel mesh of thickness 0.05mm and area 1.6 cm2 by using the compaction load of 10,000psi. 1M solution of LiClO4 in tetrahydrofuran (THF) was used for the electrolyte and a constant value of 0.65mA/cm2 as the current density was used for the charge-discharge studies. The open circuit voltage was observed to be 3.201V and the energy density obtained from the discharge capacity was 120 Wh/kg.
EXAMPLE - 2
1.6324gm of ammonium molybdate tetrahydrate (AM) and 0.1143gm of boric acid (BA) was mixed with 1gm of (PPS) poly-phenylene sulphide in the molar ratio of 1:0.2:1 in a
pestle and mortar using water as solvent. Dry mixture was then pressed into pellets of thickness 2mm and diameter 8mm by the application of a compaction load of 5OOOpsi. These pellets were then heated in nitrogen environment at temperature 410°C for two hours followed by slow cooling to room temperature. The residual product obtained at 410°C was again repelletised and heated in nitrogen atmosphere at 550°C for two hours followed by slow cooling to room temperature. Residual product obtained at 550°C was then used for fabricating cathodes. This nano-composite was mixed with PTFE binder (in the ratio of 95:5 by weight) and then pressed on nickel mesh of thickness 0.05mm and area 1.65cm2 by using the compaction load of 10,000psi. 1M solution of LiAsF6 in 1:1 mixture of propylene carbonate and tetrahydrofuran was used for the electrolyte and a constant value 0.166mA/cm as the current density was used for the charge-discharge studies. The open circuit voltage was observed to be 2.8V and, the energy density obtained from the discharge capacity was 96Wh/kg.
EXAMPLE - 3
1.6324gm of ammonium molybdate tetrahydrate (AM) was mixed with 1gm of poly-phenylene sulphide (PPS) in the molar ratio of 1:1 in a pestle and mortar using water as solvent. Dry mixture was then pressed into pellets of thickness 2mm and diameter 8mm by the application of a compaction load of 5OOOpsi. These pellets were then heated in nitrogen environment at temperature 550°C for two hours followed by slow cooling to room temperature. The residual product obtained at 550°C was again repelletised and heated in nitrogen atmosphere at 800°C for two hours followed by slow cooling to room temperature. Residual product obtained at 800°C was then used for fabricating cathode. This nano-composite was mixed with PTFE binder (in the ratio of 95:5 by weight) and

was then pressed on nickel mesh of thickness 0.05mm and area 0.8cm2 by using the compaction load of lOOOOpsi. 1M solution of LiClO4 in propylene carbonate was used for electrolyte. 0.65 mA/cm current density was used for charge-discharge operation. The open circuit voltage was observed to be 2.902V and energy density obtained from discharge capacity was 217 Wh/kg.
EXAMPLE-4
1.6786gm of ammonium molybdate tetrahydrate (AM) was mixed with Igm of poly-2-vinylpyridine (PVP) in the molar ratio of 1:1 in a pestle and mortar using water as solvent. Dry mixture was then pressed into pellets of thickness 2mm and 8 mm diameter by the application of a load of 5OOOpsi. These pellets were then heated at temperature 410°C and then at 550°C for two hours followed by slow cooling to room temperature. Residual product material was then mixed with the PTFE binder in the ratio of 95:5 by weight percent to make cathode electrode. To make the cathode electrode this mixture was then pressed on nickel mesh of thickness 0.05mm and 1cm2 area by using the load of lOOOOpsi. 1M solution of LiPF6 in propylene carbonate was used for electrolyte. 0.25 mA/cm2 current density was used for charge-discharge studies. The open circuit voltage was observed to be 3.01V and energy density obtained from discharge capacity was 115.6 Wh/kg.

We Claim:
1. A process for the preparation of nanocomposite cathode material which comprises
preparing a mixture of a polymer and an inorganic salt of a transition metal selected
from D-block of the periodic table such as herein described, at a ratio 1:1, in
water/organic solvent, drying the said mixture at a temperature ranging between
100 to 250°C, palletizing the dried mixture by conventional methods, heating the said
pellets to a temperature ranging between 400 to 800°C in inert atmosphere and
finally sintering the resultant by known methods to obtain nano-composite cathode
material.
2. A process as claimed in claim 1 wherein, the polymer used is selected from poly-1,4-
phenylene sulphide, poly-2-vinyl pyridine, poly-phenylene oxide, poly-phenylene
selenide, poly-phenylene telluride and poly-acrylonitrile.
3. A process as claimed n claim 1 wherein, the inorganic salt of metal is selected from
one or more of the group consisting of tartrates, oxalates, halides, nitrates, citrates
and ammonium salts of one or more metals selected from the group consisting of V,
Mo, Cd, Y, Ni, W, Ba, Ti and Sn, preferably ammonium molybadate and vandate.
4. A process claimed in claim 1, wherein the solvent used is water or organic solvents
such as acetone, butanol, ethanol, benzene, isopropanol.
5. A process as claimed in claim 1, wherein the palletizing is done by compaction
pressure applied is in the range of 4000 to 10000 psi; preferably 5000 to 5500 psi.
6. A process as claimed in claim 1, wherein inert atmosphere is created using nitrogen,
argon and helium.
7. A process for the preparation of nanocomposite cathode material described herein
before with reference to examples.

Documents:

1207-del-2000-abstract.pdf

1207-del-2000-claims.pdf

1207-del-2000-correspondence-others.pdf

1207-del-2000-correspondence-po.pdf

1207-del-2000-description (complete).pdf

1207-del-2000-form-1.pdf

1207-del-2000-form-19.pdf

1207-del-2000-form-2.pdf

1207-del-2000-form-3.pdf

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Patent Number

218201

Indian Patent Application Number

1207/DEL/2000

PG Journal Number

24/2008

Publication Date

13-Jun-2008

Grant Date

31-Mar-2008

Date of Filing

26-Dec-2000

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	PARTHASARATHY GANGULY	NATIONAL CHEMICAL LABORATORY, PUNE-411008, MAHARASHTRA, INDIA.
2	NARAYANASASTRI NATARAJAN	NATIONAL CHEMICAL LABORATORY, PUNE-411008, MAHARASHTRA, INDIA.
3	YOGESH BABAN KHOLLAM	NATIONAL CHEMICAL LABORATORY, PUNE-411008, MAHARASHTRA, INDIA.
4	KRISANU BANDYOPADHYAY	NATIONAL CHEMICAL LABORATORY, PUNE-411008, MAHARASHTRA, INDIA.
5	KUNJUKRISHNA PILLAI VIJAYAMOHANAN	NATIONAL CHEMICAL LABORATORY, PUNE-411008, MAHARASHTRA, INDIA.

PCT International Classification Number

H01M 4/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA