# US 11,909,046 B2 · Synthetic methods for crystallite size control of bimetallic polyanionic battery compositions

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- Number: US 11,909,046 B2
- Document ID: US11909046B2
- Status: Granted
- Kind: B2
- Application number: 15/914,192
- Filed: 2018-03-07
- Published: 2018-09-13
- Granted: 2024-02-20
- Earliest claimed: 2017-03-07
- Assignees: The Research Foundation for The State University of New York
- Applicants: The Research Foundation for The State University of New York
- Inventors: Kenneth J. Takeuchi; Esther S. Takeuchi; Amy C. Marschilok
- Web page: https://patentgrep.com/patent/US11909046B2

## CPC

- H01M 4/5825: {Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines}
- C01B 25/45: containing plural metal, or metal and ammonium
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- C01P 2002/60: Compounds characterised by their crystallite size
- C01P 2002/72: by d-values or two theta-values, e.g. as X-ray diagram
- C01P 2002/77: by unit-cell parameters, atom positions or structure diagrams
- C01P 2002/82: by IR- or Raman-data
- C01P 2002/88: by thermal analysis data, e.g. TGA, DTA, DSC
- C01P 2004/03: obtained by SEM
- C01P 2006/40: Electric properties
- H01M 2004/028: {Positive electrodes}
- 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

Bimetallic polyanionic materials, such as silver vanadium phosphorus oxide (Ag2VO2PO4, SVOP), are promising cathode materials for Li batteries due in part to their large capacity and high current capability. A new synthesis of Ag2VO2PO4 based on microwave heating is disclosed, where the reaction time is reduced by approximately 100 times relative to other reported methods, and the crystallite size is controlled via synthesis temperature, showing a linear positive correlation of crystallite size with temperature. Reaction times of an hour or less are sufficient to render phase-pure material after reaction at 50° C. to 180° C., significantly lower than the temperatures reported for other methods. Crystallite sizes between 42 nm and 60 nm are achieved by the novel method, smaller than by other methods. Silver/vanadium atomic ratios of 1.96 to 2.04 in the as-synthesized SVOP result and appear temperature-dependent. Notably, under galvanostatic reduction, the Ag2VO2PO4 sample with the smallest crystallite size delivers the highest capacity and shows the highest loaded voltage.

## Claims

### Claim 1

A method of controlling an average crystallite size of a composition comprising silver vanadium phosphorus oxide, the method comprising:
selection a reaction temperature and a reaction time;
heating a mixture of vanadium oxide (V2O5), silver oxide (Ag2O), phosphoric acid (H3PO4), and water using microwave energy to the reaction temperature;
holding the mixture at the reaction temperature under microwave irradiation for the reaction time to form the silver vanadium phosphorus oxide composition; and
cooling the silver vanadium phosphorus oxide composition to room temperature, such that the average crystallite size of the silver vanadium phosphorus oxide composition is attained, wherein the average crystallite size of the silver vanadium phosphorus oxide composition is less than about 100 nm, and wherein the silver vanadium phosphorus oxide composition has a surface area of from 5.7 m2/g to 7.5 m2/g, and an atomic ratio of silver to vanadium between 1.96 and 2.

### Claim 2 (depends on 1)

The method of claim 1, wherein: the reaction temperature is between 50° C. and 180° C.

### Claim 3 (depends on 1)

The method of claim 1, wherein:
the attained average crystallite size of the silver vanadium phosphorous oxide is between 42 nm and 60 nm.

### Claim 4 (depends on 3)

The method of claim 3, wherein the attained average crystallite size of the silver vanadium phosphorus oxide is 42 nm.

### Claim 5

A composition comprising silver vanadium phosphorus oxide having an average crystallite size less than about 100 nm and a surface area of from 5.7 m2/g to 7.5 m2/g, wherein an atomic ratio of silver to vanadium in the silver vanadium phosphorous oxide is 2.0.

### Claim 6 (depends on 5)

The composition of claim 5, wherein the average crystallite size is between 42 nm and 60 nm.

### Claim 7 (depends on 6)

The composition of claim 6, wherein the average crystallite size is 42 nm.

### Claim 8

A composition comprising silver vanadium phosphorus oxide having an average crystallite size less than about 100 nm and a surface area of from 5.7 m2/g to 7.5 m2/g, and wherein an atomic ratio of silver to vanadium in the sliver vanadium phosphorus oxide is between 1.96 and 2.04.

### Claim 9 (depends on 8)

The composition of claim 8, wherein the average crystallite size is maintained between 42 nm and 60 nm, including maintaining the atomic ratio of silver to vanadium in the silver vanadium phosphorus oxide between 1.96 and 2.04.

### Claim 10 (depends on 9)

The composition of claim 9, wherein the average crystallite size is maintained at 42 nm, including maintaining the atomic ratio of silver to vanadium in the silver vanadium phosphorus oxide at about 2.

### Claim 11

A composition comprising silver vanadium phosphorus oxide having an average crystallite size less than about 100 nm, a surface area of from 5.7 m2/g to 7.5 m2/g, and an atomic ratio of silver to vanadium between 1.96 and 2.04 prepared by a process comprising the steps of:
combining vanadium oxide (V2O5), silver oxide (Ag2O), phosphoric acid (H3PO4, and pure water (H2O) at room temperature;
heating the combined vanadium oxide (V2O5), silver oxide (Ag2O), phosphoric acid (H3PO4), and pure water (H2O) using microwave energy at a ramp rate to a reaction temperature;
maintaining the heated, combined vanadium oxide (V2O5), silver oxide (Ag2O), phosphoric acid (H3PO4), and pure water (H2O) at the reaction temperature for a reaction time to form a silver vanadium phosphorous oxide composition; and
cooling the silver vanadium phosphorous oxide composition to room temperature.

### Claim 12 (depends on 11)

The composition of claim 11, wherein the average crystallite size is between 42 nm and 60 nm.

### Claim 13 (depends on 12)

The composition of claim 12, wherein the average crystallite size is maintained at 42 nm including maintaining an atomic ratio of silver to vanadium in the silver vanadium phosphorus oxide at about 2.