# US 2017/0288263 A1 · Solid-state electrolytes for lithium batteries and process for production thereof

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- Number: US 2017/0288263 A1
- Document ID: US20170288263A1
- Status: Published application
- Kind: A1
- Application number: 15/508,494
- Filed: 2015-08-19
- Published: 2017-10-05
- Earliest claimed: 2014-09-05
- Assignees: Forschungszentrum Juelich GmbH
- Applicants: Forschungszentrum Juelich GmbH
- Inventors: Qianli MA; Frank TIETZ; Olivier GUILLON
- Web page: https://patentgrep.com/patent/US20170288263A1

## CPC

- H01M 10/0562: Solid materials
- C01B 25/45: containing plural metal, or metal and ammonium
- H01M 10/052: Li-accumulators
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 12/08: composed of a half-cell of a fuel-cell type and a half-cell of the secondary-cell type
- C01P 2006/40: Electric properties
- H01M 2300/0065: Solid electrolytes
- H01M 2300/0068: inorganic
- Y02E 60/10: Energy storage using batteries
- H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C}
- C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A method for preparing a lithium titanium phosphate, wherein a sol-gel process is used to prepare the phosphate, includes producing a sol from source materials; converting the sol to a gel; and drying the gel to obtain a corresponding powder comprising the lithium titanium phosphate. In a substep, the method further includes adding titanium(IV) isopropoxide to water to produce precipitates of titanium hydroxide oxide, cooling a system down to a temperature of less than 10° C., and redissolving the precipitates by adding nitric acid to form an aqueous TiO2+ nitrate solution. The lithium titanium phosphate has a general composition Li1+x+yMxTi2−x(PO4)3−y(SiO4)y, wherein M=Al, Ga, In, Sc, V, Cr, Mn, Co, Fe, Y, La-Lu, wherein 0≦x≦0.5, and wherein 0≦y≦0.5.

## Claims

### Claim 1

A method for preparing a lithium titanium phosphates having a general composition Li1+x+yMxTi2−x(PO4)3−y(SiO4)y, wherein M=Al, Ga, In, Sc, V, Cr, Mn, Co, Fe, Y, La-Lu, wherein 0≦x≦0.5, and wherein 0≦y≦0.5, and wherein a sol-gel process is used to prepare the phosphates, the method comprising:
producing a sol is from source materials,
converting the sol to a gel, and
drying the gel to obtain a corresponding powder comprising the lithium titanium phosphate,
wherein in a substep, the method comprises:
adding titanium(IV) isopropoxide to water to produce, precipitates of titanium hydroxide oxide,
cooling a system of the precipitates down to a temperature of less than 10° C. and
redissolving the precipitates by adding nitric acid, to form an aqueous TiO2+ nitrate solution.

### Claim 2 (depends on 1)

The method according to claim 1, wherein a polycarboxylic acid is added to the aqueous TiO2+ nitrate solution resulting in the formation of a stable aqueous TiO2+ nitrate solution even at room temperature.

### Claim 3 (depends on 1)

The method according to claim 1, wherein at least one of citric acid, fumaric acid, or tartaric acid is added to the aqueous TiO2+ nitrate solution.

### Claim 4 (depends on 1)

The method according to claim 1, wherein an aqueous solution of at least one of lithium salts and M salts is provided, wherein M=Al, Ga, In, Sc, V, Cr, Mn, Co, Fe, Y, La-Lu,
wherein an aqueous solution of Li and M salts is mixed with the aqueous TiO2+ nitrate solution, and
wherein the aqueous mixture of Li and M salts and the aqueous TiO2+ nitrate solution is cooled down to temperatures of less than 10° C. before adding a phosphate salt, resulting in the formation of the sol.

### Claim 5 (depends on 1)

The method according to of claim 1, wherein lithium is used in a form of lithium nitrate, lithium acetate, lithium carbonate, or lithium hydroxide.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the M salts are used in a form of nitrates, acetates, carbonates, or hydroxides.

### Claim 7 (depends on 1)

The method according to claim 1, wherein phosphoric acid and/or NH4H2PO4 is added as a phosphate salt.

### Claim 8 (depends on 7)

The method according to claim 7, wherein a soluble silicate, an orthosilicic acid, or an alkyl ester of the orthosilicic acid is added to the aqueous solution before adding the phosphate salt.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the sol is converted continuously to a gel by heating the sol to room temperature.

### Claim 10 (depends on 1)

The method according to claim 1, wherein the lithium titanium phosphate is compacted at room temperature at pressures of between 50 and 200 MPa and then sintered without pressure at temperatures of between 820 and 1050° C.

### Claim 11 (depends on 1)

A lithium titanium phosphate having a general composition Li1+x+yMxTi2−x(PO4)3−y(SiO4)y, wherein M=AI, Ga, In, Sc, V, Cr, Mn, Co, Fe, Y, La-Lu, wherein 0≦x≦0.5, wherein 0≦y≦0.5, the lithium titanium phosphate being prepared using the method according to claim 1.

### Claim 12 (depends on 11)

The lithium titanium phosphate according to claim 11, wherein the lithium titanium phosphate has a density of more than 99% of a theoretical density.

### Claim 13 (depends on 1)

A solid-state electrolyte for use in a lithium battery or an Li/air battery, the solid-state electrolyte comprising:
a lithium titanium phosphate with a general composition Li1+x+yMxTi2−x(PO4)3−y(SiO4)y, wherein M=Al, Ga, In, Sc, V, Cr, Mn, Co, Fe, Y, La-Lu, wherein 0≦x≦0.5 and 0≦y≦0.5, the lithium titanium phosphate being prepared according to claim 1.

### Claim 14 (depends on 13)

The solid-state electrolyte according to claim 13, wherein the solid state electrolyte comprises Li1.5Al0.5Ti1.5(PO4)3, Li1.4Y0.4Ti1.6(PO4)3, Li1.3La0.3Ti1.7(PO4)3, Li2Sc0.5Ti1.5(PO4)2.5(SiO4)0, or Li1.8Al0.4Ti1.6(PO4)2.6(SiO4)0.4.