# US 12,224,427 B2 · Secondary battery having improved high-temperature properties

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- Number: US 12,224,427 B2
- Document ID: US12224427B2
- Status: Granted
- Kind: B2
- Application number: 16/842,282
- Filed: 2020-04-07
- Published: 2020-12-17
- Granted: 2025-02-11
- Earliest claimed: 2019-06-12
- Assignees: SK On Co., Ltd.
- Applicants: SK Innovation Co., Ltd.
- Inventors: Jae Yun Min; Jeong A Kim; Sung Jun Park; Da Bin Chung; Jae Kyu Jin; Ji Hwan Choi
- Web page: https://patentgrep.com/patent/US12224427B2

## CPC

- H01M 4/366: {as layered products}
- H01M 4/364: {as mixtures}
- H01M 4/505: of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
- 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 4/622: {being polymers}
- H01M 4/625: {Carbon or graphite}
- H01M 4/626: {Metals}
- H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
- H01M 2004/021: {Physical characteristics, e.g. porosity, surface area}
- 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
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A secondary battery comprising a positive electrode current collector, a first positive electrode mixture layer disposed on the positive electrode current collector and including a first positive electrode active material and a binder, and a second positive electrode mixture layer disposed on the first positive electrode mixture layer and including a second positive electrode active material and a binder. A nickel content of the second positive electrode active material is 80% by weight or less of a nickel content of the first positive electrode active material. By providing a secondary battery including a positive electrode of a multi-layer structure that includes positive electrode active materials having different contents of nickel, a secondary battery capable of improving high-temperature characteristics while maintaining energy density may be provided.

## Claims

### Claim 1

A secondary battery comprising:
a positive electrode current collector;
a first positive electrode mixture layer disposed on the positive electrode current collector and including a first positive electrode active material and a binder; and
a second positive electrode mixture layer disposed on the first positive electrode mixture layer and including a second positive electrode active material and a binder,
wherein the first positive electrode active material is a lithium transition metal oxide comprising nickel, manganese and cobalt, and contains 42% by weight or more of nickel,
wherein the second positive electrode active material is a lithium transition metal oxide comprising nickel, manganese and cobalt, and contains 37% by weight or less of nickel,
wherein a nickel content of the second positive electrode active material is 62.9% by weight or less of a nickel content of the first positive electrode active material,
wherein the amount of the second positive electrode active material in the second positive electrode mixture layer is 50% by weight or less of the amount of the first positive electrode active material in the first positive electrode mixture layer, and
wherein an average nickel content of the first positive electrode active material in the first positive electrode mixture layer and the second positive electrode active material in the second positive electrode mixture layer is 44% by weight or less.

### Claim 2 (depends on 1)

The secondary battery of claim 1, wherein a thickness of the first positive electrode mixture layer is 30 μm to 100 μm.

### Claim 3 (depends on 1)

The secondary battery of claim 1, wherein a thickness of the second positive electrode mixture layer is 1 μm to 50 μm.

### Claim 4 (depends on 1)

The secondary battery of claim 1, wherein the first positive electrode active material is at least one selected from LiNi0.7Co0.15Mn0.15O2, LiNi0.8Co0.1Mn0.1O2, and LiNi0.9Co0.05Mn0.05O2.

### Claim 5 (depends on 1)

The secondary battery of claim 1, wherein the second positive electrode active material is at least one selected from LiNi(1/3)Co(1/3)Mn(1/3)O2, LiNi0.4Co0.3Mn0.3O2, LiNi0.5Co0.2Mn0.3O2, and LiNi0.6Co0.2Mn0.2O2.

### Claim 6 (depends on 1)

The secondary battery of claim 1, wherein the binder is at least one selected from polyvinylidene fluoride (PVDF), polyvinyl alcohol, carboxymethylcellulose (CMC), starch, hydroxypropyl cellulose, regenerated cellulose, polyvinylpyrrolidone, tetrafluoroethylene, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butylene rubber (SBR), hydrogenated nitrile butadiene rubber (H-NBR), fluorine rubber, styrene monomer (SM), Butadiene (BD), butyl acrylate (BA), mussel protein, a polyolefin-based binder, and a silane-based binder.

### Claim 7 (depends on 1)

The secondary battery of claim 1, wherein the first positive electrode mixture layer and the second positive electrode mixture layer further comprise a conductive material.

### Claim 8 (depends on 7)

The secondary battery of claim 7, wherein the conductive material is at least one selected from a multi-wall CNT, a single-wall CNT, natural graphite, artificial graphite, carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, summer black, a carbon fiber, a metal fiber, a carbon fluoride powder, an aluminum powder, a nickel powder, a zinc oxide, a potassium titanate, a titanium oxide, and a polyphenylene derivative.