Title of Invention	"A PROCESS FOR THE SYNTHESIS OF LITHIUM ALUMINIUM COBALTITE (LIAL0.5CO0.5O2) USEFUL AS CATHODE MATERIAL FOR REVERSIBLE LITHIUM ION CELLS"
Abstract	The present invention relates to the process for the preparation of lithium aluminum cobaltite as a useful cathode material for lithium cells. The product is a composite which is very useful for high voltage lithium reversible cells and can be prepared by mixing oxides of aluminum, cobalt with lithium hydroxide by heating together all in solid state condition. The mixture was made into paste by adding necessary quantity of glycerol and the paste was calcined at 750 deg C. LiAlo.s CO0.5 O2 is a reversible cathode material useful for high voltage cells of lithium in no aqueous media.

Title of Invention

"A PROCESS FOR THE SYNTHESIS OF LITHIUM ALUMINIUM COBALTITE (LIAL0.5CO0.5O2) USEFUL AS CATHODE MATERIAL FOR REVERSIBLE LITHIUM ION CELLS"

Abstract

The present invention relates to the process for the preparation of lithium aluminum cobaltite as a useful cathode material for lithium cells. The product is a composite which is very useful for high voltage lithium reversible cells and can be prepared by mixing oxides of aluminum, cobalt with lithium hydroxide by heating together all in solid state condition. The mixture was made into paste by adding necessary quantity of glycerol and the paste was calcined at 750 deg C. LiAlo.s CO0.5 O2 is a reversible cathode material useful for high voltage cells of lithium in no aqueous media.

Full Text	The present invention relates to the novel process for the preparation of lithium aluminium cobaltite as a useful cathode material for lithium cells. This present invention relates to the preparation of lithium aluminium cobaltite (LiAlo.5 Coo.5 O2) a composite, which is very useful for high voltage lithium reversible cells and can be prepared by mixing oxides of aluminium, cobalt with lithium hydroxide by heating together all in solid state condition. LiAlo.5Coo.5 O2 is a reversible cathode material useful for high voltage cells of lithium in nonaqueous media. LiAlo.5Coo.5O2 compound is hexagonal material is well known from 1995 as a good battery cathode for reversibility in nonaqueous solutions. This compound can be prepared from LiOH, Co3O4 and A1(OH)3 plus a small amount of A1(NO3)3 were mixed and heated in air first at 550°C for 20 hrs and then at 750°C for 24 hrs. [H.Huang et al, J.Power Sources, 81-82 (1992)690]. This compound can be alternatively obtained by Co-precipitation and freeze drying technique, in which an aqueous solutions of A1(NO3)3, Co(NO3)2 and LiNO3 were mixed together. Then the mixture was fired for 2 hrs at 700-800°C in air or oxygen [Y.I Jang, B.Huang, Wang, G R Maskaly and H.Tamura, J.Power sources 81-82 (1999)589]. In all the above procedures available in the literature some disadvantages were observed. They areas follow: Phase impurity Longer duration of thermal preparation High temperature of operation pH control Several steps of preparation The object of this invention is to provide a process for synthesis of lithium aluminum cobaltite (LiAlo.5 Coo.5 O2) under novel reaction method which obviates the defects and draw backs hither to known in other methods of preparation of this compound from already known procedures in literatures. Another object of this present invention is to formulate a new procedure for the synthesis of a thermal procedure for the synthesis of LiAlo.5 Coo.5 O2) cathode material for reversible lithium ion cells which obviate the draw backs of the known method. Further object of this invention in the cyclability of the system by retaining in the cathode & replacing a part of it by Aluminum. Still another object is to use glycerol as a binding agent that make a uniform homogeneous mixture which permits uniform reaction to occur without any side reaction. Yet another object of this invention is to prepare LiAlo.5 Coo.5 O2with various oxide of aluminum and cobalt and hydroxide of lithium. 8. According the present invention relates to a A process for the synthesis of lithium aluminum cobaltite (LiAlo.5 Coo.5O2) useful as cathode material for reversible lithium ion cells which comprises preparing a paste by mixing hydroxide of lithium with oxide of aluminum and cobalt in the ratio of Li: Al: Co as 1: 1/2: 1/2 by wt. respectively in presence of binding agent such as herein described, heating the said paste initially upto 200° c and then up to 800°C for a period in the range of 10-12 hr to get LiAlo.s Coo.5 O2. The temperature of preparation of the material is in between 200°C to 800°C for 12 hours. In the embodiment of this invention mixture of glycerol and urea may be used a s a binding agents for hydroxide and oxides. Hydroxide of lithium & oxides of Al & Co were powdered to fine size by grinding in them the above mixture in a pestle & mortar arrangement. In this mixture a small quantity of glycerol was added & was ground well to ensure a fine paste. The paste was transferred into a ceramic or porecelain crucible & then heated slowly in a muffle furnace initially for to 200°C temperature and finally to 800°C for 12 hrs. The reactant is cooled to room temperature and has grounded well & examined by x-ray for confirming the identify of the product & purity. A novel method of preparing this compound viz, LiAlo.5Coo.5O4 was carried out by uniform mixing of oxides of Al 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, Al2O3 and Co3O4 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 7500C 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 gray in colour and was homogenous. X-ray analysis confirmed the formation of LiAlo.sCoo.sOa according to Fig. 1. An uniform homogenous mixture of the ground compounds viz., oxides of aluminium and cobalt with LiOH were made into a paste to get a product of high purity. Glycerol was used as a solvent for binding the oxides viz., aluminium and cobalt with LiOH for making a paste of required consistency. The addition of glycerol enhanced the product of fine particles. 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 be construed the scope of this invention. Example -1 Components LiOH 0.839 gm Co3O4 0.803 gm A1203 0.510gm Flux (urea) 2.402 gm Binder (Glycerol) 2 ml Temperature 200°C - 800°C Duration of heating 12hrs Colour of the product gray Efficiency of the product 90% Phase Single Single electrode potential of LiAlo.5Co0.5 w.r.t. Li in IM LiClO4 3.01v In propylene carbonate Example - 2 Components LiOH 0.839 gm Co304 0.803 gm A1203 O.5lOgm Flux (urea) 2.402 gm Binder (Glycerol) 2 ml Temperature 200°C - 800°C Duration of heating 12hrs Colour of the product gray Efficiency of the product 90% Phase Single Single electrode potential of LiAlo.5Coo.5 w.r.t. Li in 1M LiClO4 3.01 v In propylene carbonate Novelty of the process This invention which describes the process has only one step for the preparation of the product. The process does not require any pH control or other complicated procedure. Glycerol which is used as a binder which controls the single step The product obtained is pure as evidenced by x-ray analysis. We Claim: 1. A process for the synthesis of lithium aluminum cobaltite (LiAlo.5 Coo.5O2) useful as cathode material for reversible lithium ion cells which comprises preparing a paste by mixing hydroxide of lithium with oxide of aluminum and cobalt in the ratio of Li: Al: Co as 1: 1/2: 1/2 by wt. respectively in presence of binding agent such as herein described, heating the said paste initially upto 200° c and then up to 800°C for a period in the range of 10-12 hr to get LiAlo.s Co0.5 O2. 2. A process as claimed in claim 1 when all reactants react uniformly. 3. A process as claimed in claims 1-2 wherein fine particles of the reactants LiOH, Al2O3 and Co3O4were bound by glycerol and made the mixture into a paste for uniform reaction during heating. 4. A process as claimed in claims 1-3 wherein glycerol is used as a binder for the inorganic solid state reactants. 5. A process as claimed in claims 1-4 wherein a single phase component LiAlo.5 Coo.5O2 free from impurities as evidenced by x-ray analysis. 6. A process as claimed in claims 1-5 wherein addition of glycerol as a binder has no influence in the formation of the final product. 7. A process for the synthesis of lithium aluminum cobaltite (LiAlo.5Coo.5O2) cathode material for reversible lithium ion cells substantially as herein described with reference to the examples and drawing accompanying the specification.

Full Text

The present invention relates to the novel process for the preparation of lithium aluminium cobaltite as a useful cathode material for lithium cells.
This present invention relates to the preparation of lithium aluminium cobaltite (LiAlo.5 Coo.5 O2) a composite, which is very useful for high voltage lithium reversible cells and can be prepared by mixing oxides of aluminium, cobalt with lithium hydroxide by heating together all in solid state condition. LiAlo.5Coo.5 O2 is a reversible cathode material useful for high voltage cells of lithium in nonaqueous media. LiAlo.5Coo.5O2 compound is hexagonal material is well known from 1995 as a good battery cathode for reversibility in nonaqueous solutions. This compound can be prepared from LiOH, Co3O4 and A1(OH)3 plus a small amount of A1(NO3)3 were mixed and heated in air first at 550°C for 20 hrs and then at 750°C for 24 hrs. [H.Huang et al, J.Power Sources, 81-82 (1992)690].
This compound can be alternatively obtained by Co-precipitation and freeze drying technique, in which an aqueous solutions of A1(NO3)3, Co(NO3)2 and LiNO3 were mixed together. Then the mixture was fired for 2 hrs at 700-800°C in air or oxygen [Y.I Jang, B.Huang, Wang, G R Maskaly and H.Tamura, J.Power sources 81-82 (1999)589].
In all the above procedures available in the literature some disadvantages were observed. They areas follow:
Phase impurity
Longer duration of thermal preparation
High temperature of operation
pH control
Several steps of preparation
The object of this invention is to provide a process for synthesis of lithium aluminum cobaltite (LiAlo.5 Coo.5 O2) under novel reaction method which obviates the defects and draw backs hither to known in other methods of preparation of this compound from already known procedures in literatures.
Another object of this present invention is to formulate a new procedure for the synthesis of a thermal procedure for the synthesis of LiAlo.5 Coo.5 O2) cathode material for reversible lithium ion cells which obviate the draw backs of the known method. Further object of this invention in the cyclability of the system by retaining in the cathode & replacing a part of it by Aluminum.
Still another object is to use glycerol as a binding agent that make a uniform homogeneous mixture which permits uniform reaction to occur without any side reaction. Yet another object of this invention is to prepare LiAlo.5 Coo.5 O2with various oxide of aluminum and cobalt and hydroxide of lithium.
8. According the present invention relates to a A process for the synthesis of lithium aluminum cobaltite (LiAlo.5 Coo.5O2) useful as cathode material for reversible lithium ion cells which comprises preparing a paste by mixing hydroxide of lithium with oxide of aluminum and cobalt in the ratio of Li: Al: Co as 1: 1/2: 1/2 by wt. respectively in presence of binding agent such as herein described, heating the
said paste initially upto 200° c and then up to 800°C for a period in the range of 10-12 hr to get LiAlo.s Coo.5 O2.
The temperature of preparation of the material is in between 200°C to 800°C for 12 hours.
In the embodiment of this invention mixture of glycerol and urea may be used a s a binding agents for hydroxide and oxides.
Hydroxide of lithium & oxides of Al & Co were powdered to fine size by grinding in them the above mixture in a pestle & mortar arrangement. In this mixture a small quantity of glycerol was added & was ground well to ensure a fine paste. The paste was transferred into a ceramic or porecelain crucible & then heated slowly in a muffle furnace initially for to 200°C temperature and finally to 800°C for 12 hrs. The reactant is cooled to room temperature and has grounded well & examined by x-ray for confirming the identify of the product & purity.
A novel method of preparing this compound viz, LiAlo.5Coo.5O4 was carried out by uniform mixing of oxides of Al 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, Al2O3 and Co3O4 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 7500C 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 gray in colour and was homogenous. X-ray analysis confirmed the formation of LiAlo.sCoo.sOa according to Fig. 1.
An uniform homogenous mixture of the ground compounds viz., oxides of aluminium and cobalt with LiOH were made into a paste to get a product of high purity. Glycerol was used as a solvent for binding the oxides viz., aluminium and cobalt with LiOH for making a paste of required consistency. The addition of glycerol enhanced the product of fine particles.
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 be construed the scope of this invention. Example -1 Components
LiOH 0.839 gm
Co3O4 0.803 gm
A1203 0.510gm
Flux (urea) 2.402 gm
Binder (Glycerol) 2 ml
Temperature 200°C - 800°C
Duration of heating 12hrs
Colour of the product gray
Efficiency of the product 90%
Phase Single
Single electrode potential of
LiAlo.5Co0.5 w.r.t. Li in IM LiClO4 3.01v
In propylene carbonate
Example - 2 Components
LiOH 0.839 gm
Co304 0.803 gm
A1203 O.5lOgm
Flux (urea) 2.402 gm
Binder (Glycerol) 2 ml
Temperature 200°C - 800°C
Duration of heating 12hrs
Colour of the product gray
Efficiency of the product 90%
Phase Single
Single electrode potential of
LiAlo.5Coo.5 w.r.t. Li in 1M LiClO4 3.01 v
In propylene carbonate
Novelty of the process
This invention which describes the process has only one step for the
preparation of the product.
The process does not require any pH control or other complicated procedure. Glycerol which is used as a binder which controls the single step The product obtained is pure as evidenced by x-ray analysis.

We Claim:
1. A process for the synthesis of lithium aluminum cobaltite (LiAlo.5 Coo.5O2) useful
as cathode material for reversible lithium ion cells which comprises preparing a
paste by mixing hydroxide of lithium with oxide of aluminum and cobalt in the
ratio of Li: Al: Co as 1: 1/2: 1/2 by wt. respectively in presence of binding agent
such as herein described, heating the said paste initially upto 200° c and then up to
800°C for a period in the range of 10-12 hr to get LiAlo.s Co0.5 O2.
2. A process as claimed in claim 1 when all reactants react uniformly.
3. A process as claimed in claims 1-2 wherein fine particles of the reactants LiOH,
Al2O3 and Co3O4were bound by glycerol and made the mixture into a paste for
uniform reaction during heating.
4. A process as claimed in claims 1-3 wherein glycerol is used as a binder for the
inorganic solid state reactants.
5. A process as claimed in claims 1-4 wherein a single phase component LiAlo.5
Coo.5O2 free from impurities as evidenced by x-ray analysis.
6. A process as claimed in claims 1-5 wherein addition of glycerol as a binder has no
influence in the formation of the final product.
7. A process for the synthesis of lithium aluminum cobaltite (LiAlo.5Coo.5O2)
cathode material for reversible lithium ion cells substantially as herein described
with reference to the examples and drawing accompanying the specification.

Documents:

368-del-2001-abstract.pdf

368-del-2001-claims.pdf

368-del-2001-correspondence-others.pdf

368-del-2001-correspondence-po.pdf

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

368-del-2001-drawings.pdf

368-del-2001-form-1.pdf

368-del-2001-form-18.pdf

368-del-2001-form-2.pdf

368-del-2001-form-3.pdf

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Patent Number

231567

Indian Patent Application Number

368/DEL/2001

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

06-Mar-2009

Date of Filing

27-Mar-2001

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110 001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	THIAGARAJAN VASUDEVAN	PROF. & HEAD. ALAGAPPA UNIVERSITY, KARAIKUDI-630 003, INDIA.
2	ANGAIAH SUBRAMANIAN	INDUSTRIAL CHEMISTRY ALAGAPPA UNIVERSITY, KARAIKUDI-630 003, INDIA.
3	ARIYANAN MANI	CECRI, KARAIKUDI-630 003, INDIA.
4	RAMAIYER GANGADHARAN	EMERITUS SCIENTIST, ALAGAPPA UNITERSITY, KARAIKUDI-630 003, INDIA.

PCT International Classification Number

C01D 15/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA