# US 5,700,597 A · Method for preparing Li.sub.1+x Mn.sub.2-x-y M.sub.y O.sub.4 for use in lithium batteries

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- Number: US 5,700,597 A
- Document ID: US5700597A
- Status: Granted
- Kind: A
- Application number: 08/568,244
- Filed: 1995-12-06
- Granted: 1997-12-23
- Earliest claimed: 1995-11-24
- Assignees: Moli Energy (1990) Limited
- Inventors: Qiming Zhong; Ulrich Von Sacken; Yuan Gao; Jeffery Raymond Dahn
- Web page: https://patentgrep.com/patent/US5700597A

## CPC

- H01M 4/505: of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 10/056: characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Spinel insertion compounds Li.sub.1+x Mn.sub.2-x-y M.sub.y O.sub.4 wherein M is a transition metal, 0<x< about 0.33, 0.ltoreq.y<about 1, can have relatively low surface area at relatively large values of x when prepared with a novel two step heating method. Li.sub.1 Mn.sub.2-y M.sub.y O.sub.4 is first prepared between a critical temperature, T.sub.c, and about 900.degree. C. Then, a lithium salt is mixed therewith and reacted at a temperature between about 400.degree. C. and T.sub.c. These compounds are suitable for use as a cathode in a lithium battery. The use of LiCl as the lithium salt can provide improved cycle life results in such a battery.

## Claims

### Claim 1

A methed for making an insertion compound having the formula Li.sub.1+x Mn.sub.2-x-y M.sub.y O.sub.4 wherein M is a transition metal, x is a number greater than zero and less than 0.33, y is a number greater than or equal to zero and less than about 1, the insertion compound having a spinel-phase crystal structure, and a maximum critical temperature for phase stability T.sub.c ; said method comprising selecting a process from the group consisting of:
(a) (1) heating a stoichiometric mixture of a first lithium salt and a first manganese compound at a temperature in the range from greater than T.sub.c but less than about 900.degree. C. so that an intermediate compound and having the approximate formula Li.sub.1 Mn.sub.2-y M.sub.y O.sub.4 and a spinel-phase crystal structure is obtained;
(2) mixing a stoichiometric amount of the intermediate compound and a second lithium salt selected to obtain said insertion compound at a temperature less than T.sub.c ; and
(3) heating the stoichiometric amount of said intermediate compound and said second lithium salt at a temperature in the range from greater than 400.degree. C. to less than about T.sub.c so that said insertion compound having the formula Li.sub.1+x Mn.sub.2-x-y M.sub.y O.sub.4 is obtained; and
(b) heating a stoichiometric mixture of LiCl and a second manganese compound at a reaction temperature in the range from greater than about 400.degree. C. to less than about T.sub.c, so that said insertion compound having the formula Li.sub.1+x Mn.sub.2-x-y M.sub.y O.sub.4 is obtained.

### Claim 2

A method for making an insertion compound having the formula Li.sub.1+x Mn.sub.2-x-y M.sub.y O.sub.4 wherein M is a transition metal, x is a number greater than zero and less than 0.33, y is a number greater than or equal to zero and less than about 1, the insertion compound having a spinel-phase crystal structure and a maximum critical temperature for phase stability T.sub.c, comprising:
(a) heating a stoichiometric mixture of a first lithium salt and a first manganese compound at a temperature in the range from greater than T.sub.c but less than about 900.degree. C. so that an intermediate compound having the approximate formula Li.sub.1 Mn.sub.2-y M.sub.y O.sub.4 and a spinel-phase crystal structure is obtained;
(b) mixing a stoichiometric amount of the intermediate compound and a second lithium salt selected to obtain said insertion compound at a temperature less than T.sub.c ; and
(c) heating the stoichiometric amount of said intermediate compound and said second lithium salt at a temperature in the range from greater than about 400.degree. C. to less than about T.sub.c, so that said insertion compound having the formula Li.sub.1+x Mn.sub.2-x-y M.sub.y O.sub.4 is obtained.

### Claim 3 (depends on 2)

A method for making an insertion compound as claimed in claim 2 wherein y is greater than zero and M is Ni.

### Claim 4 (depends on 2)

A method for making an insertion compound as claimed in claim 2 wherein y is zero.

### Claim 5 (depends on 4)

A method for making an insertion compound as claimed in claim 4 wherein T.sub.c is approximately given by the equation: T.sub.c =(850-1250*x).degree. C.

### Claim 6 (depends on 4)

A method for making an insertion compound as claimed in claim 4 wherein x is greater than about 0.05 and less than about 0.2.

### Claim 7 (depends on 6)

A method for making an insertion compound as claimed in claim 6 wherein the final reaction temperature is in the range from greater than about 400.degree. C. to less than about 790.degree. C.

### Claim 8 (depends on 2)

A method for making an insertion compound as claimed in claim 2 wherein the intermediate reaction temperature is about 900.degree. C.

### Claim 9 (depends on 2)

A method for making an insertion compound as claimed in claim 2 wherein the mixing temperature is ambient temperature.

### Claim 10 (depends on 2)

A method for making an insertion compound as claimed in claim 2 wherein the intermediate reactant manganese compound is electrolytic manganese dioxide.

### Claim 11 (depends on 2)

A method for making an insertion compound as claimed in claim 2 wherein the intermediate reactant lithium salt is Li.sub.2 CO.sub.3.

### Claim 12 (depends on 2)

A method for making an insertion compound as claimed in claim 2 wherein the final reactant lithium salt is selected from the group consisting of LiCl, LiF, and Li.sub.2 CO.sub.3.

### Claim 13

A method for making an insertion compound Li.sub.1+x Mn.sub.2-x-y M.sub.y O.sub.4 wherein M is a transition metal, x is a number greater than zero and less than 0.33, y is a number greater than or equal to zero and less than about 1, the insertion compound having a spinel-phase crystal structure and a maximum critical temperature for phase stability T.sub.c, comprising heating a stoichiometric mixture of LiCl and a first manganese compound at a reaction temperature in the range from greater than about 400.degree. C. to less than about T.sub.c, so that the insertion compound having the formula Li.sub.1+x Mn.sub.2-x-y M.sub.y O.sub.4 is obtained.

### Claim 14 (depends on 13)

A method for making an insertion compound as claimed in claim 13 wherein y is zero.

### Claim 15 (depends on 14)

A method for making an insertion compound as claimed in claim 14 wherein T.sub.c is approximately given by the equation: T.sub.c =(850-1250*x).degree. C.

### Claim 16 (depends on 14)

A method for making an insertion compound as claimed in claim 14 wherein x is greater than about 0.1 and less than about 0.2.

### Claim 17 (depends on 16)

A method for making an insertion compound as claimed in claim 16 wherein the lattice parameter of the insertion compound is in the range from greater than about 8.18 .ANG. to less than about 8.22 .ANG..

### Claim 18 (depends on 16)

A method for making an insertion compound as claimed in claim 16 wherein the final reaction temperature is in the range from greater than about 400.degree. C. to less than about 725.degree. C.

### Claim 19 (depends on 18)

A method for making an insertion compound as claimed in claim 18 wherein the final stoichiometric mixture is heated at the final reaction temperature for at least 18 hours.

### Claim 20 (depends on 13)

A method for making an insertion compound as claimed in claim 13 wherein the manganese compound is an insertion compound intermediate having the approximate formula Li.sub.1 Mn.sub.2-y M.sub.y O.sub.4 and a spinel-phase crystal structure wherein the insertion compound intermediate is prepared by heating a stoichiometric mixture of lithium salt and a second manganese compound at a temperature greater than T.sub.c but less than about 900.degree. C.

### Claim 21 (depends on 20)

A method for making an insertion compound as claimed in claim 20 wherein the intermediate stoichiometric mixture is heated at the intermediate reaction temperature for at least 18 hours.

### Claim 22 (depends on 1, 2, 5, 6, 13, 20)

A lithium battery comprising a lithium compound anode; an electrolyte comprising a solvent and a lithium electrolyte salt; and a cathode comprising an insertion compound prepared by the method as claimed in claims 1, 2, 5, 6, 13 or 20.

### Claim 23 (depends on 22)

A lithium battery as claimed in claim 22 wherein the lithium compound anode is carbonaceous.

### Claim 24 (depends on 22)

A lithium battery as claimed in claim 22 wherein the lithium electrolyte salt is selected from the group consisting of LiBF.sub.4 and LiPF.sub.6.

### Claim 25 (depends on 22)

A lithium battery as claimed in claim 22 wherein the solvent comprises ethylene carbonate.

### Claim 26 (depends on 25)

A lithium battery as claimed in claim 25 wherein the solvent additionally comprises a carbonate solvent selected from the group consisting of propylene carbonate, diethyl carbonate, and dimethyl carbonate.