Indian Patents. 231772:"A NOVEL PROCESS FOR THE SYNTHESIS OF LITHIUM IRON COBALTALE, USEFUL AS CATHODE MATERIAL FOR LITHIUM ION CELLS"

Title of Invention	"A NOVEL PROCESS FOR THE SYNTHESIS OF LITHIUM IRON COBALTALE, USEFUL AS CATHODE MATERIAL FOR LITHIUM ION CELLS"
Abstract	A novel process for the synthesis of lithium iron cobaltate, useful as battery cathode material for lithium ion cells which comprises: heating a paste, prepared by mixing lithium hydroxide with oxides of nickel and iron 1:1:1 respectively in glycerol and flux to a temperature up to 800°C for a maximum period of 12 hours, cooling the above product to get lithium iron cobaltate (LiFe0.5 CO0.5 O2).

Full Text	The presents invention relates to a novel process for the synthesis of lithium iron cobaltate, useful as battery cathode material for lithium ion cells. The present invention relates to the preparation of lithium iron cobaltate (LiFe0.5 CO0.5 O2) a composite, which is very useful for high voltage lithium reversible cells and can be prepared by mixing oxides of ferric, cobalt with lithium hydroxide by heating together all in solid state condition. LiFe0.5 CO0.5 O2 is a reversible cathode material useful for high voltage cells of lithium in non-aqueous, polymer electrolyte and solid state cells. The object of this invention is to synthesis LiFe0.5 CO0.5 O2 under suitable solid state reaction method which obviates the defects and draw backs hither to known in other methods of preparation of this compound from already known procedure in literature. CO0.5 O2 compound is a hexagonal material is well known from 1999 as a good battery cathode for reversibility in non-aqueous solutions. This compound can be prepared by a co-precipitation method in which LiOH, Fe(OH)3 and Co(N03h were used [M.Tabuchi, K.Ado, H.Sakaebe, A.Hirano, and R. Kanno, J. Mater. Chem 9 (1999) 199] In the above procedure available in the literature some disadvantages were observed. They are as follows :- 1. Phase impurity 2. Longer duration ofthermal preparation 3. PH control 4. Several steps of preparation The main object of this patent invention is to formulate a new procedure for the synthesis of a novel paste procedure for the synthesis of LiFe0.5 CO0.5 O2 cathode material for reversible lithium ion cells which obviates the draw backs of the known methods. Further the object of this invention to ensure good cycliability with lithium based compounds and to replace partially cobalt by other materials like Fe and get better results in voltage when a cell is assembled. Still another object of this invention is to use glycerol as a binding agent to make an informally homogeneous mixture which permits even reaction to occur and their by any side or partial reaction is prevented. Yet another object of this invention is to prepare lithium iron cobaltate (LiFe0.5CO0.5O2) from mixture hydroxide of lithium and oxides Fe and Cobalt. Accordingly, the prevent invention provides a novel process for the synthesis of lithium iron cobaltate, useful as battery cathode material for lithium ion cells which comprises: heating a paste, prepared by mixing lithium hydroxide with oxides of cobalt and iron 1:1:1 respectively in glycerol and flux to a temperature up to 800°C for a maximum period of 12 hours, cooling the above product to get lithium iron cobaltate (LiFe0.5CO0.5 02). In an embodiment of this invention the temperature of preparation may be in the range of 600°C to 800°C. In another embodiment of this invention glycerol is used as a binding agent. Yet in another embodiment of this invention urea, ammonium nitrite, ammonium formate, succinic acid, formamide may be used as precursors. A novel method of preparing this compound viz., LiFe0.5Co0.5O2 was carried out by uniform mixing of oxides of Fe and Co with LiOH and this mixture was made into a paste by adding necessary quantity of glycerol and the paste was calcined at 750°C continuously for 12 hrs in a furnace. The prepared product was subjected to x-ray analysis. The product was found to be in single phase. The present invention, describes the method of synthesis of cathode material for a secondary battery, by heating a paste prepared by mixing fine particles of LiOH, Fe2O3 and(Co3O4) in glycerol. The paste was initially heated slowly in a furnace to evaporate off glycerol in order to get a dried mass at 200 - 250°C. This dried mass was then continuously heated to 800°C for 12 hrs. The compound formed was slowly cooled to room temperature and was ground well and then examined for its particles size, colour and structure. It was found that the prepared sample was brown in colour and was homogenous, X-rays analysis confirmed the formation of LiFe0.5Co0.5 O2 according to Fig. 1. The present invention describes a novel paste procedure for the synthesis of LiFe0.5Co0.5O2 cathode material for reversible lithium ion cells which comprises of heating hydroxide of lithium and oxide Fe and Cobalt for the preparation lithium iron cobaltate. The above mixture was ground well with a pestle & mortar to get a fine powder. This powder was mixed with small quantities of glycerol and was ground well to get a paste which was transformed into a porcelain / ceramic crucible and then was slowly heated to 200°C initially & then was strongly heated to 800°C for 12 hours. The resultant product was cooled slowly and then examined it by x-ray to conformity purity & identity (the composites of the mixture of Li: Fe : Co is in the molar ratio of 1 : 1 : 1. The novelty of this process lies in the follqwing aspects. This method yields pure products without undergoing partial reactions or side reactions. The other procedure know is cumbersome and needs several steps where as this process needs only one step. Excess of flux addition has no deleterious effect on the product. The following advantages are claimed in this invention for the preparation of LiFe0.5Co0.5O2 An uniform homogeneous mixture of the compounds viz., oxides of ferric and cobalt which LiOH were made into a paste to get a product of high purity. Glycerol was used as a solvent for biding the oxides viz., ferric and cobalt with LiOH for making a paste of required consistency. The addition of glycerol enhanced the quality of the product to very fine size. The addition of flux (urea) / excess addition of glycerol (solvent) as a binding material for oxides does not change the colour or quality of the end product. The following examples are given by the way of illustration and should not Beconstrued the scope of this invention. The following examples give the way of synthesizing LiFe0.5Co0.5O2 Example -1 Components LiOH 0.839 gm Fe203 0.80 gm Co3O4 0.80 gm Flux (urea) 2.402 gm Binder (Glycerol) 2 ml Temperature 200°C - 800°C Duration of heating 12hrs Colour of the product brown Efficiency of the product 92% Phase Single Single electrode potential of LiFe0.5Co0.5 02 w.r.t. Li in 1MHC1O4 3.01 v In propylene carbonate. As standard procedure is followed to measure the single electrode potential. Hydroxide of lithium, and oxides of cobalt and iron were ground well using a pestle and mortar arrangement. After grinding the powder to a fine particle size, glycerol was added to this powder in small quantities and ground well to form a fine paste. The paste was then heated initially to 200°C and strongly heated to 800°C and maintained the temperature for 12 hours. The product formed was cooled to room temperature and was then examined by x-ray to identify the product and its purity. Example - 2 Components LiOH 0.839 gm Fe2O3 0.80 gm Co3O4 0.80 gm Flux (urea) 3 gm Binder (Glycerol) 3 ml Temperature 200°C - 800°C Duration of heating 12hrs Colour of the product brown Efficiency of the product brown Efficiency of the product 92% Phase Single Single electrode potential of LiFeo.sCoo.5 02 w.r.t. in 1M LiC104 3.01v In propylene carbonate. As standard procedure is followed to measure the single electrode potential. The procedure is same as given for example 1. We Claim: 1. A novel process for the synthesis of lithium iron cobaltate, useful as battery cathode material for lithium ion cells which comprises: heating a paste, prepared by mixing lithium hydroxide with oxides of cobalt and iron 1:1:1 respectively in glycerol and flux to a temperature up to 800°C for a maximum period of 12 hours, cooling the above product to get lithium iron cobaltate (LiFeo.5CO0.5 O2). 2. A process as claimed in claim 1 wherein glycerol is used as a binder for the inorganic solid state reactants. 3. A process as claimed in claims 1-2 wherein process leaves a single phase component LiCoo 5 Fe0.5 free from impurities as evidenced by x-ray analysis. 4. A process claimed in claims 1-3 wherein the product is be used rocking chair cells for solid state, polymer electrolyte and nonaqueous call as cathode electrode. 5. A process as claimed in claims 1-4 wherein heating is carried muffle furnace initially at a temperature of 200°C and finally at 800°C. 6. A novel process for the synthesis of lithium iron cobaltate, useful as battery cathode material for lithium ion cells substantially as herein described with reference to the examples.

Full Text

The presents invention relates to a novel process for the synthesis of lithium iron cobaltate, useful as battery cathode material for lithium ion cells.
The present invention relates to the preparation of lithium iron cobaltate (LiFe0.5 CO0.5 O2) a composite, which is very useful for high voltage lithium reversible cells and can be prepared by mixing oxides of ferric, cobalt with lithium hydroxide by heating together all in solid state condition. LiFe0.5 CO0.5 O2 is a reversible cathode material useful for high voltage cells of lithium in non-aqueous, polymer electrolyte and solid state cells.
The object of this invention is to synthesis LiFe0.5 CO0.5 O2 under suitable solid state reaction method which obviates the defects and draw backs hither to known in other methods of preparation of this compound from already known procedure in literature.
CO0.5 O2 compound is a hexagonal material is well known from 1999 as a good battery cathode for reversibility in non-aqueous solutions. This compound can be prepared by a co-precipitation method in which LiOH, Fe(OH)3 and Co(N03h were used [M.Tabuchi, K.Ado, H.Sakaebe, A.Hirano, and R. Kanno, J. Mater. Chem 9 (1999) 199]
In the above procedure available in the literature some disadvantages were observed. They are as follows :-
1. Phase impurity
2. Longer duration ofthermal preparation
3. PH control
4. Several steps of preparation
The main object of this patent invention is to formulate a new procedure for the synthesis of a novel paste procedure for the synthesis of LiFe0.5 CO0.5 O2 cathode material for reversible lithium ion cells which obviates the draw backs of the known methods.
Further the object of this invention to ensure good cycliability with lithium based compounds and to replace partially cobalt by other materials like Fe and get better results in voltage when a cell is assembled.
Still another object of this invention is to use glycerol as a binding agent to make an informally homogeneous mixture which permits even reaction to occur and their by any side or partial reaction is prevented.
Yet another object of this invention is to prepare lithium iron cobaltate (LiFe0.5CO0.5O2) from mixture hydroxide of lithium and oxides Fe and Cobalt.
Accordingly, the prevent invention provides a novel process for the synthesis of lithium iron cobaltate, useful as battery cathode material for lithium ion cells which comprises: heating a paste, prepared by mixing lithium hydroxide with oxides of cobalt and iron 1:1:1 respectively in glycerol and flux to a temperature up to 800°C for a maximum period of 12 hours, cooling the above product to get lithium iron cobaltate (LiFe0.5CO0.5 02).
In an embodiment of this invention the temperature of preparation may be in the range of 600°C to 800°C.
In another embodiment of this invention glycerol is used as a binding agent.
Yet in another embodiment of this invention urea, ammonium nitrite, ammonium formate, succinic acid, formamide may be used as precursors.
A novel method of preparing this compound viz., LiFe0.5Co0.5O2 was carried out by uniform mixing of oxides of Fe and Co with LiOH and this mixture was made into a paste by adding necessary quantity of glycerol and the paste was calcined at 750°C continuously for 12 hrs in a furnace. The prepared product was subjected to x-ray analysis. The product was found to be in single phase.
The present invention, describes the method of synthesis of cathode material for a secondary battery, by heating a paste prepared by mixing fine particles of LiOH, Fe2O3 and(Co3O4) in glycerol. The paste was initially heated slowly in a furnace to evaporate off glycerol in order to get a dried mass at 200 - 250°C. This dried mass was then continuously heated to 800°C for 12 hrs. The compound formed was slowly cooled to room temperature and was ground well and then examined for its particles size, colour and structure. It was found that the prepared sample was brown in colour and was homogenous, X-rays analysis confirmed the formation of LiFe0.5Co0.5 O2 according to Fig. 1.
The present invention describes a novel paste procedure for the synthesis of LiFe0.5Co0.5O2 cathode material for reversible lithium ion cells
which comprises of heating hydroxide of lithium and oxide Fe and Cobalt for the preparation lithium iron cobaltate. The above mixture was ground well with a pestle & mortar to get a fine powder. This powder was mixed with small quantities of glycerol and was ground well to get a paste which was transformed into a porcelain / ceramic crucible and then was slowly heated to 200°C initially & then was strongly heated to 800°C for 12 hours. The resultant product was cooled slowly and then examined it by x-ray to conformity purity & identity (the composites of the mixture of Li: Fe : Co is in the molar ratio of 1 : 1 : 1.
The novelty of this process lies in the follqwing aspects.
This method yields pure products without undergoing partial reactions or side reactions.
The other procedure know is cumbersome and needs several steps where as this process needs only one step.
Excess of flux addition has no deleterious effect on the product.
The following advantages are claimed in this invention for the preparation of LiFe0.5Co0.5O2
An uniform homogeneous mixture of the compounds viz., oxides of ferric and cobalt which LiOH were made into a paste to get a product of high purity.
Glycerol was used as a solvent for biding the oxides viz., ferric and cobalt with LiOH for making a paste of required consistency. The addition of glycerol enhanced the quality of the product to very fine size.
The addition of flux (urea) / excess addition of glycerol (solvent) as a binding material for oxides does not change the colour or quality of the end product.
The following examples are given by the way of illustration and should not Beconstrued the scope of this invention.
The following examples give the way of synthesizing
LiFe0.5Co0.5O2
Example -1
Components
LiOH 0.839 gm
Fe203 0.80 gm
Co3O4 0.80 gm
Flux (urea) 2.402 gm
Binder (Glycerol) 2 ml
Temperature 200°C - 800°C
Duration of heating 12hrs
Colour of the product brown
Efficiency of the product 92%
Phase Single
Single electrode potential of
LiFe0.5Co0.5 02 w.r.t. Li in 1MHC1O4 3.01 v
In propylene carbonate.
As standard procedure is followed to measure the single electrode potential.
Hydroxide of lithium, and oxides of cobalt and iron were ground well using a pestle and mortar arrangement. After grinding the powder to a fine particle size, glycerol was added to this powder in small quantities and ground well to form a fine paste. The paste was then heated initially to 200°C and strongly heated to 800°C and maintained the temperature for 12 hours. The product formed was cooled to room temperature and was then examined by x-ray to identify the product and its purity.
Example - 2 Components
LiOH 0.839 gm
Fe2O3 0.80 gm
Co3O4 0.80 gm
Flux (urea) 3 gm
Binder (Glycerol) 3 ml
Temperature 200°C - 800°C
Duration of heating 12hrs
Colour of the product brown
Efficiency of the product brown
Efficiency of the product 92%
Phase Single
Single electrode potential of
LiFeo.sCoo.5 02 w.r.t. in 1M LiC104 3.01v
In propylene carbonate.
As standard procedure is followed to measure the single electrode potential.
The procedure is same as given for example 1.

We Claim:
1. A novel process for the synthesis of lithium iron cobaltate, useful as battery cathode
material for lithium ion cells which comprises: heating a paste, prepared by mixing
lithium hydroxide with oxides of cobalt and iron 1:1:1 respectively in glycerol
and flux to a temperature up to 800°C for a maximum period of 12 hours, cooling
the above product to get lithium iron cobaltate (LiFeo.5CO0.5 O2).
2. A process as claimed in claim 1 wherein glycerol is used as a binder for the
inorganic solid state reactants.
3. A process as claimed in claims 1-2 wherein process leaves a single phase
component LiCoo 5 Fe0.5 free from impurities as evidenced by x-ray analysis.
4. A process claimed in claims 1-3 wherein the product is be used rocking chair cells
for solid state, polymer electrolyte and nonaqueous call as cathode electrode.
5. A process as claimed in claims 1-4 wherein heating is carried muffle furnace
initially at a temperature of 200°C and finally at 800°C.
6. A novel process for the synthesis of lithium iron cobaltate, useful as battery cathode
material for lithium ion cells substantially as herein described with reference to the
examples.

Documents:

355-del-2001-abstract.pdf

355-del-2001-claims.pdf

355-del-2001-correspondence-others.pdf

355-del-2001-correspondence-po.pdf

355-del-2001-description (complete).pdf

355-del-2001-drawings.pdf

355-del-2001-form-1.pdf

355-del-2001-form-18.pdf

355-del-2001-form-2.pdf

355-del-2001-form-3.pdf

« Previous Patent

Next Patent »

Patent Number

231772

Indian Patent Application Number

355/DEL/2001

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

09-Mar-2009

Date of Filing

27-Mar-2001

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	ANGAIAH SUBRAMANIAN	INDUSTRIAL CHEMISTRY, ALAGAPPPA UNIVERSITY, KARAKUDI 630 003, TAMIL NADU, INDIA.
2	ARIYANAN MANI	CENTRAL ELECTRO-CHEMICAL RESEARCH INSTITUTE, KARAIKUDI 630 006, TAMILNADU, INDIA.
3	THIAGARAJAN VASUDEVAN	INDUSTRIAL CHEMISTRY, ALAGAPPA UNIVERSITY, KARAIKUDI 630 003, TAMILNADU, INDIA.
4	RAMAIYER GANGADHARAN	INDUSTRIAL CHEMISTRY, ALAGAPPA UNIVERSITY, KARAIKUDI 630 003, TAMILNADU, INDIA.

PCT International Classification Number

C01G 51/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA