# US 2026/0100356 A1 · Positive electrode for lithium-ion secondary battery and lithium-ion secondary battery

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- Number: US 2026/0100356 A1
- Document ID: US20260100356A1
- Status: Published application
- Kind: A1
- Application number: 19/349,207
- Filed: 2025-10-03
- Published: 2026-04-09
- Earliest claimed: 2024-10-07
- Assignees: Toyota Jidosha Kabushiki Kaisha
- Applicants: Toyota Jidosha Kabushiki Kaisha
- Inventors: Yuusuke SHIMIZU
- Web page: https://patentgrep.com/patent/US20260100356A1

## CPC

- H01M 4/366: {as layered products}
- H01M 4/131: Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
- H01M 4/136: Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
- 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 4/5825: {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 2004/021: {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

The teaching herein provides an electrode for a lithium-ion secondary battery with excellent input/output characteristics, using an olivine type compound and a layered rocksalt type oxide as its positive electrode active materials. The description herein provides a positive electrode for a lithium-ion secondary battery. This positive electrode for a lithium-ion secondary battery comprises: a positive electrode current collector layer; and a positive electrode composite layer containing an olivine-type compound and a layered rocksalt-type oxide as its positive electrode active materials. The positive electrode composite layer comprises a first region on a side that is closer to a first surface of the positive electrode composite layer, the first surface being opposite to a second surface of the positive electrode composite layer facing the positive electrode current collector layer, and the first region contains the layered rocksalt-type oxide at a higher concentration.

## Claims

### Claim 1

A positive electrode for a lithium-ion secondary battery, the positive electrode comprising:
a positive electrode current collector layer; and
a positive electrode composite layer containing an olivine-type compound and a layered rocksalt-type oxide as its positive electrode active materials,
wherein the positive electrode composite layer comprises a first region on a side that is closer to a first surface of the positive electrode composite layer, the first surface being opposite to a second surface of the positive electrode composite layer facing the positive electrode current collector layer, and
the first region contains the layered rocksalt-type oxide at a higher concentration.

### Claim 2 (depends on 1)

The positive electrode according to claim 1, wherein the positive electrode composite layer comprises the first region in a form of a layer.

### Claim 3 (depends on 1)

The positive electrode according to claim 1, wherein
the positive electrode composite layer comprises a second region on a side that is closer to the second surface of the positive electrode composite layer, and
the second region does not contain the layered rocksalt-type oxide or contains the layered rocksalt-type oxide at a lower concentration.

### Claim 4 (depends on 2)

The positive electrode according to claim 2, wherein
the positive electrode composite layer comprises a second region on a side that is closer to the second surface of the positive electrode composite layer, and
the second region does not contain the layered rocksalt-type oxide or contains the layered rocksalt-type oxide at a lower concentration.

### Claim 5 (depends on 1)

The positive electrode according to claim 1, wherein the layered rocksalt-type oxide contains an oxide represented by Formula (1) or (2):
(where M1 represents one, or two or more elements selected from Mg, Ti, Nb, Fe, Cr, Si, Al, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi, and Ge; and a, b, c, and w represent numbers that satisfy 0.3≤a<1, 0<b≤0.7, 0<c≤0.7, 0≤w≤0.3, and 3a+3b+3c+ (valence of M1)×w=3 in Formula (1)
(where M2 represents one, or two or more elements selected from Mg, Ti, Nb, Fe, Cr, Si, Ga, V, Zn, Cu, Sr, Mo, Zr, Sn, Ta, W, La, Ce, Pb, Bi, and Ge; and d, e, f, and x represent numbers satisfying 0.4≤d<1, 0<e≤0.5, 0<f≤0.3, 0≤x≤0.3, and 3d+3e+3f+ (valence of M2)×x=3 in Formula (2)).

### Claim 6 (depends on 5)

The positive electrode according to claim 5, wherein the layered rocksalt type oxide contains an oxide represented by Formula (1).

### Claim 7 (depends on 6)

The positive electrode according to claim 6, wherein the oxide represented by Formula (1) contains 50 mol % or more and 80 mol % or less of Ni.

### Claim 8 (depends on 1)

The positive electrode according to claim 1, wherein the olivine-type compound contains a compound represented by Formula (3):
(where M3 represents one or more elements selected from Mg, Al, Ti, Cu, Zn, Nb, Co, Ni, Ca, Sr, Y, Zr, Mo, Ba, Pb, Bi, La, Ce, Nd, and Gd; and g, h, i, and y represent numbers satisfying 0≤g≤1.2, 0≤h≤1.2, and 0≤i≤1.2, provided that h+i is not 0, 0≤y≤0.3, and g+(valence of Mn)×h+(valence of Fe)×i+(valence of M3)×y=3. in Formula (3)).

### Claim 9 (depends on 8)

The positive electrode according to claim 8, wherein the olivine-type compound contains 20 mol % or more of Mn.

### Claim 10 (depends on 1)

A lithium-ion secondary battery comprising:
a positive electrode according to claim 1;
a negative electrode; and
a separator.