Title of Invention	A NOVEL PROCESS FOR THE PREPARATION OF LITHIUM COBALT VANADATE (LICoVO4) USEFUL AS CATHODE MATERIAL FOR THE SECONDARY LITHIUM ION CELLS
Abstract	This invention relates to a novel process for the preparation of lithium cobalt vanadate useful as cathode material for secondary lithium ion cells. The lithium cobalt vanadate (LiCoVO4) is a composite material which is very useful for high voltage lithium secondary cells, and can be prepared by mixing oxides of cobalt & vanadium with lithium hydroxide by solid state reaction. Cobalt vanadate of lithium is useful as a positive electrode material for reversible rechargeable secondary cells based on lithium. The process yields pure products without under going partial reactions or side reaction because of glycerol as a binding agent.

Title of Invention

A NOVEL PROCESS FOR THE PREPARATION OF LITHIUM COBALT VANADATE (LICoVO4) USEFUL AS CATHODE MATERIAL FOR THE SECONDARY LITHIUM ION CELLS

Abstract

This invention relates to a novel process for the preparation of lithium cobalt vanadate useful as cathode material for secondary lithium ion cells. The lithium cobalt vanadate (LiCoVO4) is a composite material which is very useful for high voltage lithium secondary cells, and can be prepared by mixing oxides of cobalt & vanadium with lithium hydroxide by solid state reaction. Cobalt vanadate of lithium is useful as a positive electrode material for reversible rechargeable secondary cells based on lithium. The process yields pure products without under going partial reactions or side reaction because of glycerol as a binding agent.

Full Text	This invention relates to a novel process for preparation of lithium cobalt vanadate useful as cathode material for secondary lithium ion cells. This invention particulate relates to the preparation of lithium cobalt vanadate (LiCoVO4) a composite material which is very useful for high voltage lithium secondary cells, and can be prepared by mixing oxides of cobalt & vanadium with lithium hydroxide by solid state reaction. Cobalt vanadate of lithium is useful as a positive electrode material for reversible rechargeable secondary cells based on lithium. The present invention relates to a process of preparation of lithium cobalt vanadate useful as a battery cathode material for lithium cells. Studies on the inverse spinel LiCoO4 can be traced back 1994 onwards. It was already established that this spinel compound was able to intercalate / deintercalate in a nonaqueous medium when used as an electrode in a lithium battery. This compound was prepared by heating an appropriate stochiometric ratio of Li2CO3, CoCO3, and VaO5 at 430°C for several days. [C.Gonzalez, M.Gaitan, M.L. Lopez, M.L. Veiga, R. Saez-puche, and C.Pico, J.Materials science, 29 (1994) 3458]. In the above procedure, the following disadvantages are observed. 1. Phase impurity 2. Longer duration of thermal preparation The main objects of this present invention is to formulate a new procedure for the synthesis of process for preparation of LiCoVO4 useful as cathode material for the secondary lithium ion cells which obviate the draw backs by the known methods. Further object of this invention is retain Co for increased cycliability with the cathode material and at the same time to introduce vanadium to increase the voltage of the all. Still another object is to use glycerol a binding agent to make an uniform homogenous mixture which permits uniform reaction to occur without any side reaction. Yet another object of this invention is to prepare of preparation of lithium cobalt vanadate useful as a battery cathode material for lithium cells. The novelty of the process lies in the following aspects. This method yields pure products without under going partial reactions or side reaction because of glycerol as a binding agent. The other procedures available in literature are cumbersome & needs several steps. This procedure in simple & needs step. Addition of excess glycerol has no deletion effect on the product quality or particle size or colour. Accordingly the present invention relates to a novel process for the preparation of lithium cobalt van date (LiCoVO4) useful as cathode material for the secondary lithium ion cells which comprises: heating a mixture of hydroxide of lithium and oxides of cobalt and vanadium prepared by mixing in molar ratio of 1:1:1 in glycerol initially at 200°C and followed by heating up to 800°C for a period of 12 hrs., cooling the product to get lithium cobalt vanadate. A novel method of preparing this compound viz., LiCoVO4 was carried out by uniform mixing of oxides of Co and vanadium with LiOH and this mixture was made into a paste by adding necessary quantity of glycerol and the paste was calcined at750°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. In an embodiment of this invention glycerol is a binding agent which does not allow partial or side reactions to occur. In yet another embodiment of this invention the temperature of operation may be between 600°C to 800°C. The present invention, describes the method of synthesis of the cathode material for a secondary battery, but heating a paste prepared by mixing fine particles of LiOH, €0304 and X^Os in glycerol. This paste was initially heated slowly in a furnace to evaporate off glycerol in order to get a dried mass at 250°C. This dried mass was then continuously heated to 750°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 XRD exposure. It was found that the prepared sample was blackish brown in coloured and was homogenous X-rays analysis confirmed the formation of LiCoVO4 according to Fig 1. The following examples are given by way of illustration and should not be construed the scope of this invitation. The following examples the illustration the synthesis of LiCoVO4 cathode material by solid state reaction. Example - 1 Compounds LiOH 1.778gm Co3O4 3.211 V2O5 3.238 gm Binder (Glycerol) 2ml Temperature 200°C - 800°C Duration of heating 12hrs Colour of the product Blackish brown Efficiency of the product 90% Phase single Single electrode potential of LiCoVO4 w.r.t. in 1M LiClO4 3.01v In propylene carbonate. A standard procedure is followed to measure the single electrode potential as the cathode. Hydroxides of lithium & oxides of cobalt & vanadium are ground well in a pestle & mortar arrangement. After grinding the mixture well the fine power is mixed with glycerol till a paste is obtained when ground well with the mortar. The paste was then heated in a crucible initially slowly till the temperature is reacted to 200°C. The dried mass was strongly heated to 800°C to get the desired product viz., LiCoVO4. The product was examined for its purity & conformation by X-ray. Example - 2 Compounds LiOH 1.778gm Co304 3.211 V2O5 3.238 gm Binder (Glycerol) 4ml Temperature 200°C - 750°C Duration of heating lOhrs Colour of the product Blackish brown Efficiency of the product 90% Phase single Single electrode potential of LiCoVO4 w.r.t. in 1M LiClO4 3.01v In propylene carbonate. The procedure used is same as disclosed in example 1 .A standard procedure is followed to measure the single electrode potential as the cathode. The following advantages are claimed in this invention for the preparation of lithium cobalt vanadate. An uniform homogeneous mixture of the reacting compounds viz., oxides of cobalt and vanadium with LiOH were made into a paste to get a product of high purity. Glycerol was used as a solvent for biding the oxides viz., cobalt and vanadium with LiOH for making a paste of required consistency. The addition of glycerol enhanced the product of fine particles. The excess addition of glycerol (solvent) as a binding material for the oxides does not change the colour or quality of the end product. We Claim: 1. A novel process for the preparation of lithium cobalt vanadate (LiCoVO4) useful as cathode material for the secondary lithium ion cells which comprises: heating a mixture of hydroxide of lithium and oxides of cobalt and vanadium prepared by mixing in molar ratio of 1:1:1 in glycerol initially at 200°C and followed by heating up to 800°C for a period of 12 hrs., cooling the product to get lithium cobalt vanadate. 2. A process as claimed in claim 1 wherein glycerol in used as binder to form a paste with the reactants viz., oxides of cobalt, vanadium with LiOH. 3. A process as claimed in claims 1-2 wherein the temperature is in between 600- 800°C. 4. A novel process for the preparation of LiCoVO4 useful as cathode material for the secondary lithium ion cells substantially as herein described with reference to the examples.

Full Text

This invention relates to a novel process for preparation of lithium cobalt vanadate useful as cathode material for secondary lithium ion cells. This invention particulate relates to the preparation of lithium cobalt vanadate (LiCoVO4) a composite material which is very useful for high voltage lithium secondary cells, and can be prepared by mixing oxides of cobalt & vanadium with lithium hydroxide by solid state reaction. Cobalt vanadate of lithium is useful as a positive electrode material for reversible rechargeable secondary cells based on lithium.
The present invention relates to a process of preparation of lithium cobalt vanadate useful as a battery cathode material for lithium cells.
Studies on the inverse spinel LiCoO4 can be traced back 1994 onwards. It was already established that this spinel compound was able to intercalate / deintercalate in a nonaqueous medium when used as an electrode in a lithium battery. This compound was prepared by heating an appropriate stochiometric ratio of Li2CO3, CoCO3, and VaO5 at 430°C for several days. [C.Gonzalez, M.Gaitan, M.L. Lopez, M.L. Veiga, R. Saez-puche, and C.Pico, J.Materials science, 29 (1994) 3458]. In the above procedure, the following disadvantages are observed.
1. Phase impurity
2. Longer duration of thermal preparation
The main objects of this present invention is to formulate a new procedure for the synthesis of process for preparation of LiCoVO4 useful as

cathode material for the secondary lithium ion cells which obviate the draw backs by the known methods.
Further object of this invention is retain Co for increased cycliability with the cathode material and at the same time to introduce vanadium to increase the voltage of the all.
Still another object is to use glycerol a binding agent to make an uniform homogenous mixture which permits uniform reaction to occur without any side reaction.
Yet another object of this invention is to prepare of preparation of lithium cobalt vanadate useful as a battery cathode material for lithium cells.
The novelty of the process lies in the following aspects. This method yields pure products without under going partial reactions or side reaction because of glycerol as a binding agent.
The other procedures available in literature are cumbersome & needs several steps. This procedure in simple & needs step. Addition of excess glycerol has no deletion effect on the product quality or particle size or colour.
Accordingly the present invention relates to a novel process for the preparation of lithium cobalt van date (LiCoVO4) useful as cathode material for the secondary lithium ion cells which comprises: heating a mixture of hydroxide of lithium and oxides of cobalt and vanadium prepared by mixing in molar ratio of 1:1:1 in glycerol initially at 200°C and followed by heating up to 800°C for a period of 12 hrs., cooling the product to get lithium cobalt vanadate.
A novel method of preparing this compound viz.,
LiCoVO4 was carried out by uniform mixing of oxides of Co and vanadium with LiOH and this mixture was made into a paste by adding necessary quantity of glycerol and the paste was calcined at750°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.
In an embodiment of this invention glycerol is a binding agent which does not allow partial or side reactions to occur.
In yet another embodiment of this invention the temperature of operation may be between 600°C to 800°C.
The present invention, describes the method of synthesis of the cathode material for a secondary battery, but heating a paste prepared by mixing fine particles of LiOH, €0304 and X^Os in glycerol. This paste was initially heated slowly in a furnace to evaporate off glycerol in order to get a dried mass at 250°C. This dried mass was then continuously heated to 750°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 XRD exposure. It was found that the prepared sample was blackish brown in coloured and was homogenous X-rays analysis confirmed the formation of LiCoVO4 according to Fig 1.
The following examples are given by way of illustration and should not be construed the scope of this invitation.
The following examples the illustration the synthesis of LiCoVO4
cathode material by solid state reaction.
Example - 1
Compounds
LiOH 1.778gm

Co3O4 3.211
V2O5 3.238 gm
Binder (Glycerol) 2ml
Temperature 200°C - 800°C
Duration of heating 12hrs
Colour of the product Blackish brown
Efficiency of the product 90%
Phase single
Single electrode potential of
LiCoVO4 w.r.t. in 1M LiClO4 3.01v
In propylene carbonate.
A standard procedure is followed to measure the single electrode potential as the cathode.
Hydroxides of lithium & oxides of cobalt & vanadium are ground well in a pestle & mortar arrangement. After grinding the mixture well the fine power is mixed with glycerol till a paste is obtained when ground well with the mortar. The paste was then heated in a crucible initially slowly till the temperature is reacted to 200°C. The dried mass was strongly heated to 800°C to get the desired product viz., LiCoVO4. The product was examined for its purity & conformation by X-ray.

Example - 2 Compounds
LiOH 1.778gm
Co304 3.211
V2O5 3.238 gm
Binder (Glycerol) 4ml
Temperature 200°C - 750°C
Duration of heating lOhrs
Colour of the product Blackish brown
Efficiency of the product 90%
Phase single
Single electrode potential of
LiCoVO4 w.r.t. in 1M LiClO4 3.01v
In propylene carbonate.
The procedure used is same as disclosed in example 1 .A standard procedure is followed to measure the single electrode potential as the cathode.
The following advantages are claimed in this invention for the preparation of lithium cobalt vanadate.
An uniform homogeneous mixture of the reacting compounds viz., oxides of cobalt and vanadium with LiOH were made into a paste to get a product of high purity.

Glycerol was used as a solvent for biding the oxides viz., cobalt and vanadium with LiOH for making a paste of required consistency. The addition of glycerol enhanced the product of fine particles.
The excess addition of glycerol (solvent) as a binding material for the oxides does not change the colour or quality of the end product.

We Claim:
1. A novel process for the preparation of lithium cobalt vanadate (LiCoVO4) useful
as cathode material for the secondary lithium ion cells which comprises: heating a
mixture of hydroxide of lithium and oxides of cobalt and vanadium prepared by
mixing in molar ratio of 1:1:1 in glycerol initially at 200°C and followed by
heating up to 800°C for a period of 12 hrs., cooling the product to get lithium
cobalt vanadate.
2. A process as claimed in claim 1 wherein glycerol in used as binder to form a paste
with the reactants viz., oxides of cobalt, vanadium with LiOH.
3. A process as claimed in claims 1-2 wherein the temperature is in between 600-
800°C.
4. A novel process for the preparation of LiCoVO4 useful as cathode material for the
secondary lithium ion cells substantially as herein described with reference to the
examples.

Documents:

524-del-2001-abstract.pdf

524-del-2001-claims.pdf

524-del-2001-correspondence-others.pdf

524-del-2001-correspondence-po.pdf

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

524-del-2001-drawings.pdf

524-del-2001-form-1.pdf

524-del-2001-form-18.pdf

524-del-2001-form-2.pdf

524-del-2001-form-3.pdf

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Patent Number

231662

Indian Patent Application Number

524/DEL/2001

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

07-Mar-2009

Date of Filing

26-Apr-2001

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH,

Applicant Address

RAFI MARG, NEW DELHI-110 001,

Inventors:

#	Inventor's Name	Inventor's Address
1	ANGAIAH SUBRAMANIAN,	INDUSTRIAL CHEMISTRY, ALAGPPA UNIVERSITY, KRAIKUDI 630003, TAMILNADU,
2	ARIYANAN MANI,	India Tamil Nadu India
3	THIAGARAJAN VASUDEVAN DEPT,	India Tamil Nadu India
4	RAMA IYER GANGADHARAN , DEPT	India Tamil Nadu India

PCT International Classification Number

H01M 10/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA