Title of Invention	A NOVEL PROCESS FOR THE PREPARATION OF LITHIUM NICKEL MANGANATE (LiNiMnO4) AS CATHODE MATERIAL FOR HIGH VOLTAGE LITHIUM CELLS
Abstract	The present invention relates to the novel process for the preparation of lithium nickel manganate (LiNiMnO4) as cathode material for high voltage lithium cells. A novel method of preparing LiNiMnO4 was developed by dissolving nitrates of lithium, nickel and manganese of the appropriate composition ration in a solution of citric acid and glycerol mixture (1:4 molar ratios) at 90°C for 15 min. The resulting clear solution was further heated to 140°C to get a high viscous solution and this viscous solution was then heated to 180°C for getting a dried mass. This mass was then heated slowly from 200°C to 600 C for 10 hrs in a furnace.

Title of Invention

A NOVEL PROCESS FOR THE PREPARATION OF LITHIUM NICKEL MANGANATE (LiNiMnO4) AS CATHODE MATERIAL FOR HIGH VOLTAGE LITHIUM CELLS

Abstract

The present invention relates to the novel process for the preparation of lithium nickel manganate (LiNiMnO4) as cathode material for high voltage lithium cells. A novel method of preparing LiNiMnO4 was developed by dissolving nitrates of lithium, nickel and manganese of the appropriate composition ration in a solution of citric acid and glycerol mixture (1:4 molar ratios) at 90°C for 15 min. The resulting clear solution was further heated to 140°C to get a high viscous solution and this viscous solution was then heated to 180°C for getting a dried mass. This mass was then heated slowly from 200°C to 600 C for 10 hrs in a furnace.

Full Text	The present invention relates to a novel process for the preparation of lithium nickel manganate (LiNiMnO4) as cathode material for high voltage lithium cells. The present invention more particularly relates to the preparation of lithium nickel manganate. (LiNiMnO4) a composite, which is very useful for high voltage lithium cells and can be prepared by chemical combustion method. The literature survey reveals the presence spinal LiMn2-xNioO4 as a solid state battery material for lithium cells of high voltage. Y.K. Sun etal has shown that this interesting compound can be synthesized in the lab by preparing solution of the soluble acetates of Li, Mn & Ni with glycine. These solution was evaporated to dryness and was heated to 300°C initially and subsequently to 800°C for 10 hrs to obtain the desired composition of LiMn2.xNixO4 {Y K Sun, D W Kim & Y M Choi, J Power Sources, 79(1999) 231]. Another literature citation describes the preparation of this compound by heating a mixture any of lithium salts like Li2CO3 LiOH / LiNO3 with any of the manganese salts like MnO2 / MnCO3 and any of nickel salt like NiO / Ni(OH)2 / Ni(NO3)2 / NiCO2O4 of definite proportions. The optimum temperature for the synthesis is 850°C. [K.Amine, H.Tukamoto, H.Yasuda & Y.Fujita, J.Electrochem, Soc., 143 (1996) 1607]. In the above mentioned methods disadvantages are phase purity difficult to controlling of pH, requires Intermittent heating, Long time of heating, high temperature range 800-850°C. The objective of this invention is a novel process for the preparation of lithium nickel manganate (LiNiMnO4) as cathode material for high voltage lithium cells, which obviates the defects and drawbacks in other methods known in the literature. The main object of this invention is to formulate a new low temperature procedure for the synthesis of LiNiMnO4 cathode material for high voltage lithium cells. Further the object of this invention to ensure good cyclability of the lithium based compound and to replace cobalt based lithium salt in order to get better working efficiency and higher voltage when the cell is assembled. Still another objective is to use glycerol as a binding agent to make an uniform homogeneous mixture which allows uniform reaction to occur during heating and does not permit side reaction to occur. Yet another object of this invention is to prepare LiNiMnO4 cathode material from nitrate source so as to reduce the temperature of formation of the compound. Accordingly the present invention relates to a novel process for the preparation of lithium nickel manganate (LiNiMnO4) as cathode material for high voltage lithium cells which comprises characterized in that heating a mixture of nitrates of lithium, manganese & nickel in molar ratio 1:1:1 respectively with citric acid and glycerol mixture 1:4 molar ratio at a temperature of 200°C initially for 30 minutes to get dried mass, heating the said dried mass from 200 deg C to 650°C for 10 hours in order to get the final product LiNiMnO4. In the embodiment of this invention the temperature of the product preparation was in between 400°C to 650°C for 10 hours. In yet another embodiment of this invention the product obtained in lithium nickel manganate. Still in another embodiment of this invention glycerol is used as a binding agent. In another embodiment of this invention the molar ratio of the components used for the formation of the product (viz. lithium nickel manganate) is as follows Li: Ni: Mn :: 1 : 1 : 1. A novel method of preparing LiNiMnO4 was developed by dissolving nitrates of lithium, nickel and manganese of the appropriate composition ration in a solution of citric acid and glycerol mixture (1:4 molar ratio) at 90°C for 15 min. The resulting clear solution was further heated to 140°C to get a high viscous solution and this viscous solution was then heated to 180oC for getting a dried mass. This mass was then heated slowly from 200°C to 600°C for lOhrs in a furnace. A fine spinel product was left behind was then cooled gradually to room temperature and was then analyzed for purity and structure by x-ray. The product obtained by this method was found to be in a single phase of high purity. The novelty of the process $ lies in the use of binding agent. This is a low temperature process The product formed is of high purity substantiated by x-ray No partial reaction occurs Simplest of all the procedures known The starting materials used are the nitrates of Li, Ni and Mn which are not used in earlier processes. The following examples are given by the way of illustration and should not be construed the scope of this invention. The following examples give the way of synthesizing LiNiMnO4 Examples -1 Components LiNO3 2.46 gm Ni(NO3)2 2.91 gm Mn(NO3)2 2.51 gm Citric acid & glycerol mixture 4 ml 1:4 molar ratio Temperature Initial heating at 200°C followed by Heating at 600°C Duration of heating l0hrs Colour of the product Dark brown Efficiency of the product 94% Phase Single Single electrode potential of LiNiMnC-4 w.r.t. Li in 1M LiClO4 3.01 v In propylene carbonate A standard procedure is followed to measure the single electrode potential of the cathode Nitrates of lithium, nickel and manganese was ground well in order to get a fine powder in a pestle & mortar arrangement. The powder was mixed with small quantities of glycerol and ground well in order to get a paste. The paste was heated initially slowly to 200°C & subsequently heated strongly to 600°C for 10 hours. The product formed was cooled in the muzzle furnace & then ground well in order to get a fine powder. The powder sample was x-rayed for ensuring the purity & identify of the compound. Examples - 2 Components LiNo3 2.46 gm Ni(NO3)2 2.91 gm Mn(NO3)2 2.51 gm Citric acid & glycerol mixture 8 ml * 1:4 molar ratio Temperature Initial heating at 200°C for 1/2 hours followed by heating at 600°C Duration of heating l0hrs Colour of the product Dark brown Efficiency of the product 94% Phase Single Single electrode potential of LiNiMnO4 w.r.t. Li in 1M LiC104 3.0Iv In propylene carbonate A standard procedure is followed to measure the single electrode potential of the cathode This present invention the following advantages are claimed for the preparation of LiNiMnO4. 1. In order to get a homogeneous mixture the reacting materials components like LiNO3 Ni(NO3)2, Mn(NO3) are dissolved in a solution of citric acid and glycerol mixture (1:4 molar ratio) to get a clear solution. 2. The homogeneous mixture on heating undergoes solid state reaction leaving behind an uniform product of high purity. 3. Glycerol was used as solvent for the reacting components so as to keep the whole mass as a viscous solution. 4. A single phase product was formed which was confirmed by x-ray analysis. 5. The presence of citric acid and glycerol mixture has no influence on the particle size of the product. 6. The precursor citric acid used for the product preparation has no influence on the quality or the colour of the final product. 7.. N62 gas produced during the reaction is innocence 8. No impurities are imparted during the reaction 9. At low temperature all nitrates decompose 10. Direct formation of the cathod material at low temperature in are step We Claim: 1. A novel process for the preparation of lithium nickel manganate (LiNiMnO4) as cathode material for high voltage lithium cells which comprises characterized in that heating a mixture of nitrates of lithium, manganese & nickel in molar ratio 1:1:1 respectively with citric acid and glycerol mixture 1:4 molar ratio at a temperature of 200°C initially for 30 minutes to get dried mass, heating the said dried mass from 200 deg C to 650°C for 10 hours in order to get the final product LiNiMnO4. 2. A process as claimed in claim 1 wherein the temperature of the product preparation preferably between 400°C to 650°C. 3. A novel process for the preparation of lithium nickel manganate (LiNiMnO4) as cathode material for high voltage lithium cells substantially as herein described with reference to the examples and drawing accompanying the specification.

Full Text

The present invention relates to a novel process for the preparation of lithium nickel manganate (LiNiMnO4) as cathode material for high voltage lithium cells. The present invention more particularly relates to the preparation of lithium nickel manganate.
(LiNiMnO4) a composite, which is very useful for high voltage lithium cells and can be prepared by chemical combustion method.
The literature survey reveals the presence spinal LiMn2-xNioO4 as a solid state battery material for lithium cells of high voltage. Y.K. Sun etal has shown that this interesting compound can be synthesized in the lab by preparing solution of the soluble acetates of Li, Mn & Ni with glycine. These solution was evaporated to dryness and was heated to 300°C initially and subsequently to 800°C for 10 hrs to obtain the desired composition of LiMn2.xNixO4 {Y K Sun, D W Kim & Y M Choi, J Power Sources, 79(1999) 231].
Another literature citation describes the preparation of this compound by heating a mixture any of lithium salts like Li2CO3 LiOH / LiNO3 with any of the manganese salts like MnO2 / MnCO3 and any of nickel salt like NiO / Ni(OH)2 / Ni(NO3)2 / NiCO2O4 of definite proportions. The optimum temperature for the synthesis is 850°C. [K.Amine, H.Tukamoto, H.Yasuda & Y.Fujita, J.Electrochem, Soc., 143 (1996) 1607].
In the above mentioned methods disadvantages are phase purity difficult to controlling of pH, requires Intermittent heating, Long time of heating, high temperature range 800-850°C.

The objective of this invention is a novel process for the preparation of lithium nickel manganate (LiNiMnO4) as cathode material for high voltage lithium cells, which obviates the defects and drawbacks in other methods known in the literature.
The main object of this invention is to formulate a new low temperature procedure for the synthesis of LiNiMnO4 cathode material for high voltage lithium cells.
Further the object of this invention to ensure good cyclability of the lithium based compound and to replace cobalt based lithium salt in order to get better working efficiency and higher voltage when the cell is assembled.
Still another objective is to use glycerol as a binding agent to make an uniform homogeneous mixture which allows uniform reaction to occur during heating and does not permit side reaction to occur.
Yet another object of this invention is to prepare LiNiMnO4 cathode material from nitrate source so as to reduce the temperature of formation of the compound.
Accordingly the present invention relates to a novel process for the preparation of lithium nickel manganate (LiNiMnO4) as cathode material for high voltage lithium cells which comprises characterized in that heating a mixture of nitrates of lithium, manganese & nickel in molar ratio 1:1:1 respectively with citric acid and glycerol mixture 1:4 molar ratio at a temperature of 200°C initially for 30 minutes to get dried mass, heating the said dried mass from 200 deg C to 650°C for 10 hours in order to get the final product LiNiMnO4.
In the embodiment of this invention the temperature of the product preparation was in between 400°C to 650°C for 10 hours.

In yet another embodiment of this invention the product obtained in lithium nickel manganate.
Still in another embodiment of this invention glycerol is used as a binding agent. In another embodiment of this invention the molar ratio of the components used for the formation of the product (viz. lithium nickel manganate) is as follows Li: Ni: Mn :: 1 : 1 : 1.
A novel method of preparing LiNiMnO4 was developed by dissolving nitrates of lithium, nickel and manganese of the appropriate composition ration in a solution of citric acid and glycerol mixture (1:4 molar ratio) at 90°C for 15 min. The resulting clear solution was further heated to 140°C to get a high viscous solution and this viscous solution was then heated to 180oC for getting a dried mass. This mass was then heated slowly from 200°C to 600°C for lOhrs in a furnace. A fine spinel product was left behind was then cooled gradually to room temperature and was then analyzed for purity and structure by x-ray. The product obtained by this method was found to be in a single phase of high purity.
The novelty of the process $ lies in the use of binding agent.
This is a low temperature process
The product formed is of high purity substantiated by x-ray
No partial reaction occurs
Simplest of all the procedures known
The starting materials used are the nitrates of Li, Ni and Mn which are not used in earlier
processes.

The following examples are given by the way of illustration and should not be construed the scope of this invention.
The following examples give the way of synthesizing LiNiMnO4
Examples -1 Components
LiNO3 2.46 gm
Ni(NO3)2 2.91 gm
Mn(NO3)2 2.51 gm
Citric acid & glycerol mixture 4 ml
1:4 molar ratio
Temperature Initial heating at 200°C followed by
Heating at 600°C
Duration of heating l0hrs
Colour of the product Dark brown
Efficiency of the product 94%
Phase Single
Single electrode potential of
LiNiMnC-4 w.r.t. Li in 1M LiClO4 3.01 v
In propylene carbonate
A standard procedure is followed to measure the single electrode potential of the cathode

Nitrates of lithium, nickel and manganese was ground well in order to get a fine powder in a pestle & mortar arrangement. The powder was mixed with small quantities of glycerol and ground well in order to get a paste. The paste was heated initially slowly to 200°C & subsequently heated strongly to 600°C for 10 hours. The product formed was cooled in the muzzle furnace & then ground well in order to get a fine powder. The powder sample was x-rayed for ensuring the purity & identify of the compound.
Examples - 2 Components
LiNo3 2.46 gm
Ni(NO3)2 2.91 gm
Mn(NO3)2 2.51 gm
Citric acid & glycerol mixture 8 ml
*
1:4 molar ratio
Temperature Initial heating at 200°C for 1/2 hours
followed by heating at 600°C
Duration of heating l0hrs
Colour of the product Dark brown
Efficiency of the product 94%
Phase Single
Single electrode potential of
LiNiMnO4 w.r.t. Li in 1M LiC104 3.0Iv
In propylene carbonate

A standard procedure is followed to measure the single electrode potential of the cathode
This present invention the following advantages are claimed for the preparation of LiNiMnO4.
1. In order to get a homogeneous mixture the reacting materials components like
LiNO3 Ni(NO3)2, Mn(NO3) are dissolved in a solution of citric acid and glycerol
mixture (1:4 molar ratio) to get a clear solution.
2. The homogeneous mixture on heating undergoes solid state reaction leaving
behind an uniform product of high purity.
3. Glycerol was used as solvent for the reacting components so as to keep the whole
mass as a viscous solution.
4. A single phase product was formed which was confirmed by x-ray analysis.
5. The presence of citric acid and glycerol mixture has no influence on the particle
size of the product.
6. The precursor citric acid used for the product preparation has no influence on the
quality or the colour of the final product.
7.. N62 gas produced during the reaction is innocence
8. No impurities are imparted during the reaction
9. At low temperature all nitrates decompose
10. Direct formation of the cathod material at low temperature in are step

We Claim:
1. A novel process for the preparation of lithium nickel manganate (LiNiMnO4) as
cathode material for high voltage lithium cells which comprises characterized in
that heating a mixture of nitrates of lithium, manganese & nickel in molar ratio
1:1:1 respectively with citric acid and glycerol mixture 1:4 molar ratio at a
temperature of 200°C initially for 30 minutes to get dried mass, heating the said
dried mass from 200 deg C to 650°C for 10 hours in order to get the final
product LiNiMnO4.
2. A process as claimed in claim 1 wherein the temperature of the product
preparation preferably between 400°C to 650°C.
3. A novel process for the preparation of lithium nickel manganate (LiNiMnO4) as
cathode material for high voltage lithium cells substantially as herein described
with reference to the examples and drawing accompanying the specification.

Documents:

364-del-2001-abstract.pdf

364-del-2001-claims.pdf

364-del-2001-correspondence-others.pdf

364-del-2001-correspondence-po.pdf

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

364-del-2001-form-1.pdf

364-del-2001-form-18.pdf

364-del-2001-form-2.pdf

364-del-2001-form-3.pdf

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Patent Number

231610

Indian Patent Application Number

364/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	ANGAIAH SUBRAMANIAN, DEPT	INDUSTRIAL CHEMISTRY, ALGAPPA UNIVERSITY, KAIRAIKUDI 6300003, TAMILNADU, INDIA.
2	ARIYANAN MANI	ELECTRO-CHEMICAL RESEARCH INSTITUTE, KAIRAIKUDI 6300003, TAMILNADU, INDIA.
3	THIAGARAJAN VASUDEVAN, DEPT	INDUSTRIAL CHEMISTRY, ALGAPPA UNIVERSITY, KAIRAIKUDI 6300003, TAMILNADU, INDIA.
4	RAMAIYER GANGADHARAN, DEPT	INDUSTRIAL CHEMISTRY, ALGAPPA UNIVERSITY, KAIRAIKUDI 6300003, TAMILNADU, INDIA.

PCT International Classification Number

H01M 4/02

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA