# US 12,009,492 B2 · Method for recycling and preparing positive electrode material from waste lithium iron phosphate batteries

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- Number: US 12,009,492 B2
- Document ID: US12009492B2
- Status: Granted
- Kind: B2
- Application number: 18/260,005
- Filed: 2022-08-11
- Published: 2024-02-22
- Granted: 2024-06-11
- Earliest claimed: 2021-11-18
- Assignees: Guangdong Brunp Recycling Technology Co., Ltd.; Hunan Brunp Recycling Technology Co., Ltd.; Yichang Brunp Contemporary Amperex Co., Ltd.
- Applicants: Guangdong Brunp Recycling Technology Co., Ltd.; Hunan Brunp Recycling Technology Co., Ltd.; Yichang Brunp Contemporary Amperex Co., Ltd.
- Inventors: Haijun Yu; Aixia Li; Yinghao Xie; Changdong Li; Xuemei Zhang; Yingsheng Zhong
- Web page: https://patentgrep.com/patent/US12009492B2

## CPC

- H01M 10/54: Reclaiming serviceable parts of waste accumulators
- C01B 25/45: containing plural metal, or metal and ammonium
- H01M 4/1397: of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
- C01P 2004/03: obtained by SEM
- C01P 2004/64: Nanometer sized, i.e. from 1-100 nanometer
- C01P 2006/40: Electric properties
- H01M 4/5825: {Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines}
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 2004/028: {Positive electrodes}
- Y02W 30/84: Recycling of batteries or fuel cells
- 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
- Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT

## Abstract

A method for recycling and preparing a positive electrode material from waste lithium iron phosphate batteries. The method comprises the following steps: discharging, crushing, and stripping waste lithium iron phosphate batteries to obtain black powder; then mixing the black powder with benzenesulfonate, and reacting in a fluidized bed; and then adding an acid and an alkali to remove impurities, finally adding a lithium supplement, an iron supplement, or a phosphate, and a reducing agent, and sintering. According to the method, by controlling and optimizing the crushing, stripping, carbon and fluorine removal, and impurity removal processes, a positive electrode material with high purity can be recycled while controlling the recycling cost, and batteries prepared by means of the recycled positive electrode material have good performance.

## Claims

### Claim 1

A method for recycling and preparing a cathode material from waste lithium iron phosphate batteries, comprising:
(1) discharging the waste lithium iron phosphate batteries, drying an electrolyte inside the waste lithium iron phosphate batteries, then crushing to obtain crushed pieces, and stripping the crushed pieces to obtain a black powder;
(2) mixing the black powder obtained in step (1) with a benzene sulfonate, and then reacting in a fluidized bed to obtain a black powder with carbon and fluorine being removed;
(3) adding an acid into the black powder with carbon and fluorine being removed in step (2), performing solid-liquid separation to obtain a solution A and a solid A; and then, adding an alkali into the solution A until no precipitation is generated, and performing solid-liquid separation to obtain a solution B and a solid B; and
(4) mixing the solid A and the solution B obtained in step (3), adding at least one of a lithium supplement agent, an iron supplement agent or a phosphate to obtain a mixture, then adding a reducing agent into the mixture, and sintering to obtain the cathode material.

### Claim 2 (depends on 1)

The method of claim 1, wherein in step (1), an area ratio of the crushed pieces to the waste lithium iron phosphate batteries is greater than 5%.

### Claim 3 (depends on 1)

The method of claim 1, wherein in step (1), the stripping comprises placing the crushed pieces in a stripping liquid, performing primary heating, and separating into a solid and a separated liquid; and then subjecting the separated liquid to secondary heating, and removing the stripping liquid to obtain the black powder.

### Claim 4 (depends on 3)

The method of claim 3, wherein the stripping liquid comprises polyol and phosphoester.

### Claim 5 (depends on 4)

The method of claim 4, wherein the polyol is selected from at least one of ethylene glycol, propylene glycol, propanetriol, 1,2-butanediol or 1,3-butanediol; and the phosphoester is selected from at least one of phosphomonoester, phosphodiester, phosphotriester, triethyl phosphate or trimethyl phosphate.

### Claim 6 (depends on 5)

The method of claim 5, wherein a volume ratio of the polyol to the phosphoester is 1:(0.1 to 1).

### Claim 7 (depends on 4)

The method of claim 4, wherein a volume ratio of the polyol to the phosphoester is 1:(0.1 to 1).

### Claim 8 (depends on 3)

The method of claim 3, wherein the primary heating is performed at a temperature of 130° C. to 210° C., and the primary heating lasts for 0.5 hour to 10 hours; and the secondary heating is performed at a temperature of 210° C. to 300° ° C., and the secondary heating lasts for 2 hours to 12 hours.

### Claim 9 (depends on 1)

The method of claim 1, wherein in step (2), an addition amount of the benzene sulfonate is 0.1 w % to 5 w % of the black powder.

### Claim 10 (depends on 9)

The method of claim 9, wherein in step (2), the benzene sulfonate is selected from at least one of sodium p-toluenesulfonate, sodium benzenesulfonate or zinc benzenesulfonate.

### Claim 11 (depends on 1)

The method of claim 1, wherein in step (2), the reacting is performed at a temperature of 300° ° C. to 850° C., and lasts for 1 minute to 360 minutes.