# US 2021/0344007 A1 · Method for producing positive electrode active material for lithium ion secondary batteries

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- Number: US 2021/0344007 A1
- Document ID: US20210344007A1
- Status: Published application
- Kind: A1
- Application number: 17/374,210
- Filed: 2021-07-13
- Published: 2021-11-04
- Earliest claimed: 2016-06-23
- Assignees: Hitachi Metals, Ltd.
- Applicants: Hitachi Metals, Ltd.
- Inventors: Hisato TOKORO; Takashi NAKABAYASHI; Shuichi TAKANO; Akira GUNJI; Tatsuya TOOYAMA; Shin TAKAHASHI
- Web page: https://patentgrep.com/patent/US20210344007A1

## CPC

- H01M 4/505: of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
- C01G 53/506: with the molar ratio of nickel with respect to all the metals other than alkali metals higher than or equal to 0.8, e.g. Li(MzNixCoyMn1-x-y-z)O2 with x ≥ 0.8
- H01M 4/525: of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
- 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
- C01P 2002/77: by unit-cell parameters, atom positions or structure diagrams
- 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
- C01G: COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F (metal hydrides {monoborane, diborane or addition complexes thereof} C01B6/00; salts of oxyacids of halogens C01B11/00; peroxides, salts or peroxyacids C01B15/00; thiosulfates, dithionites, polythionates C01B17/64; compounds containing selenium, or tellurium C01B19/00; binary compounds of nitrogen with metals C01B21/06; azides C01B21/08; {compounds containing nitrogen, other non-metals and metal C01B21/082}; metal amides C01B21/092; nitrites C01B21/50; {compounds of noble gases C01B23/0005}; phosphides C01B25/08; salts of oxyacids of phosphorus C01B25/16; carbides C01B32/90; compounds containing silicon C01B33/00; compounds containing boron C01B35/00; compounds having molecular sieve properties but not having base-exchange properties C01B37/00; compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites, C01B39/00; cyanides C01C3/08; salts of cyanamide C01C3/16; thiocyanates C01C3/20)
- 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

Making a positive electrode active material for lithium ion secondary batteries includes: weighting and mixing lithium carbonate and a compound containing respective metallic elements other than Li in a composition formula LiαNixCoyM21-x-y-zM2zO2+β so as to have a metallic constituent ratio of the formula to obtain a mixture, and firing the mixture to obtain a lithium composite compound. Performing, on the mixture, a first heat treatment at 200° C. to 400° C. for 0.5 to 5 hours to obtain a first precursor. A step of performing a heat treatment on the first precursor under an oxidizing atmosphere at 450° C. to 800° C. for 0.5 to 50 hours, and reacting 92 mass % or more of the lithium carbonate to obtain a second precursor, and a finishing step of performing a heat treatment on the second precursor under an oxidizing atmosphere at 755° C. to 900° C. for 0.5 to 50 hours to obtain the lithium composite compound.

## Claims

### Claim 1

A method for producing positive electrode active material for lithium ion secondary batteries, the method comprising:
a mixing step of weighting and mixing a lithium carbonate and a compound containing respective metallic elements other than Li in Formula (1), LiαNixCoyM11-x-y-zM2zO2+β, so as to have a metallic constituent ratio of a composition formula in accordance with the Formula (1) to obtain a mixture,
where values in the Formula (1) meet: 0.97≤α≤1.08, −0.1≤β0.1, 0.7<x≤0.9, 0.03≤y≤0.3, 0≤z≤0.1, and 0<1-x-y-z, M1 is at least one kind of an element selected from the group consisting of Mn and Al, and M2 is at least one kind of an element selected from the group consisting of Mg, Ti, Zr, Mo, and Nb; and
a firing step of firing the mixture to obtain a lithium composite compound expressed by the Formula (1),
wherein the firing step includes:
a first precursor forming step of performing a heat treatment on the mixture at a heat treatment temperature of 200° C. or more and 400° C. or less for 0.5 hours or more and 5 hours or less to obtain a first precursor;
a second precursor forming step of performing a heat treatment on the first precursor under an oxidizing atmosphere at a heat treatment temperature of 450° C. or more and 800° C. or less for 0.5 hours or more and 50 hours or less, the second precursor forming step reacting 92 mass % or more of the lithium carbonate to obtain a second precursor; and
a finishing heat treatment step of performing a heat treatment on the second precursor under an oxidizing atmosphere at a heat treatment temperature of 755° C. or more and 900° C. or less for 0.5 hours or more and 50 hours or less to obtain the lithium composite compound.

### Claim 2 (depends on 1)

The method for producing positive electrode active material for lithium ion secondary batteries according to claim 1,
wherein the heat treatment temperature in the finishing heat treatment step is 840° C. or more and 890° C. or less.

### Claim 3 (depends on 1)

The method for producing positive electrode active material for lithium ion secondary batteries according to claim 1,
wherein the second precursor forming step forms the second precursor such that 97 mass % or more of the lithium carbonate has reacted, the lithium carbonate being contained in the mixture weighted and mixed so as to have the metallic constituent ratio of the composition formula in the Formula (1).

### Claim 4 (depends on 1)

The method for producing positive electrode active material for lithium ion secondary batteries according to claim 1,
wherein the heat treatment temperature in the second precursor forming step is 600° C. or more and 700° C. or less.

### Claim 5 (depends on 1)

The method for producing positive electrode active material for lithium ion secondary batteries according to claim 1,
wherein the M1 in the Formula (1) is Mn, 0.04≤1-x-y-z≤0.18 being met.

### Claim 6 (depends on 1)

The method for producing positive electrode active material for lithium ion secondary batteries according to claim 1,
wherein the lithium composite compound is not water-washed after the finishing heat treatment step.

### Claim 7 (depends on 1)

The method for producing positive electrode active material for lithium ion secondary batteries according to claim 1, the method comprising
a step of performing a water washing on the lithium composite compound after the finishing heat treatment step.

### Claim 8 (depends on 7)

The method for producing positive electrode active material for lithium ion secondary batteries according to claim 7, the method comprising
a step of performing a drying at least once or more after the step of performing the water washing.

### Claim 9 (depends on 1)

The method for producing positive electrode active material for lithium ion secondary batteries according to claim 1, further comprising a measurement step that includes measuring an amount of reacted lithium carbonate in the second precursor after the second precursor forming step.