US-20260128324-A1 - COATED ACTIVE MATERIAL, POSITIVE ELECTRODE MATERIAL, POSITIVE ELECTRODE, AND BATTERY

Abstract

A coated active material includes a positive electrode active material and a coating layer including a first solid electrolyte and coating at least a portion of a surface of the positive electrode active material. The first solid electrolyte contains Li, Ti, M, and X, the M is at least one selected from the group consisting of metalloid elements and metal elements other than Li and Ti, and the X is at least one selected from the group consisting of F, Cl, Br, and I. A quotient obtained by the following mathematical expression (A), is 1.9 or more and 6.9 or less. Mathematical ⁢ expression ⁢ ( A ) { ( mass ⁢ of ⁢ first ⁢ solid ⁢ electrolyte ) / ( total ⁢ mass ⁢ of ⁢ positive ⁢ electrode ⁢ active ⁢ material ⁢ and ⁢ first ⁢ solid ⁢ electrolyte ) } × 100 / ( specific ⁢ surface ⁢ area ⁢ of ⁢ positive ⁢ electrode ⁢ active ⁢ material )

Inventors

• Yuta Sugimoto
• Kazuya Hashimoto
• KEITA MIZUNO

Assignees

• PANASONIC HOLDINGS CORPORATION
• TOYOTA JIDOSHA KABUSHIKI KAISHA

Dates

Publication Date

20260507

Application Date

20251219

Priority Date

20230622

Claims (11)

1. 1 . A coated active material comprising: a positive electrode active material; and a coating layer comprising a first solid electrolyte and coating at least a portion of a surface of the positive electrode active material, wherein the first solid electrolyte comprises Li, Ti, M, and X, the M is at least one element selected from the group consisting of metalloid elements and metal elements other than Li and Ti, the X is at least one selected from the group consisting of F, Cl, Br, and I, and a quotient obtained by dividing a ratio (%) of a mass of the first solid electrolyte to a total mass of the positive electrode active material and the first solid electrolyte by a specific surface area (m 2 /g) of the positive electrode active material, which is determined by the following mathematical expression (A), is 1.9 or more and 6.9 or less, {(mass of first solid electrolyte)/(total mass of positive electrode active material and first solid electrolyte)}×100/(specific surface area of positive electrode active material). mathematical expression (A):
2. 2 . The coated active material according to claim 1 , wherein the quotient is 2.7 or more and 6.2 or less.
3. 3 . The coated active material according to claim 2 , wherein the quotient is 3.5 or more and 5.0 or less.
4. 4 . The coated active material according to claim 1 , wherein the M comprises at least one selected from the group consisting of Ca, Mg, Al, Y, Ni, Fe, Cr, and Zr.
5. 5 . The coated active material according to claim 4 , wherein the M comprises Al.
6. 6 . The coated active material according to claim 1 , wherein the first solid electrolyte is represented by the following composition formula (1), where α, β, γ, and δ are each independently a value greater than 0.
7. 7 . The coated active material according to claim 1 , wherein the first solid electrolyte is represented by the following composition formula (2), where M2 is at least one selected from the group consisting of Zr, Ni, Fe, and Cr, m is a valence of the M2, and 0.1<x<0.9, 0≤y<0.1, 0≤z<0.1, and 0.8<b≤1.2 are satisfied.
8. 8 . A positive electrode material comprising: the coated active material according to claim 1 ; and a second solid electrolyte.
9. 9 . The positive electrode material according to claim 8 , wherein the second solid electrolyte comprises Li and S.
10. 10 . A positive electrode comprising the positive electrode material according to claim 8 .
11. 11 . A battery comprising the positive electrode according to claim 10 .

Description

This application is a continuation of PCT/JP2024/017534 filed on May 10, 2024, which claims foreign priority of Japanese Patent Application No. 2023-102847 filed on Jun. 22, 2023, the entire contents of both of which are incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present disclosure relates to a coated active material, a positive electrode material, a positive electrode, and a battery. 2. Description of Related Art JP 2016-18735A describes a method for producing a composite active material by coating a positive electrode active material with an oxide solid electrolyte and further with a sulfide solid electrolyte. In the conventional art, it is desired to reduce the internal resistance of a battery. SUMMARY OF THE INVENTION The present disclosure provides a coated active material including: a positive electrode active material; anda coating layer including a first solid electrolyte and coating at least a portion of a surface of the positive electrode active material, whereinthe first solid electrolyte contains Li, Ti, M, and X,the M is at least one element selected from the group consisting of metalloid elements and metal elements other than Li and Ti,the X is at least one selected from the group consisting of F, Cl, Br, and I, anda quotient obtained by dividing a ratio (%) of a mass of the first solid electrolyte to a total mass of the positive electrode active material and the first solid electrolyte by a specific surface area (m2/g) of the positive electrode active material, which is determined by the following mathematical expression (A), is 1.9 or more and 6.9 or less, mathematical⁢ expression⁢ (A){(mass⁢ of⁢ first⁢ solid⁢ electrolyte)/(total⁢ mass⁢ of⁢ positive⁢ electrode⁢ active⁢ material⁢ and⁢ first⁢ solid⁢ electrolyte)}×100/(specific⁢ surface⁢ area⁢ of⁢ positive⁢ electrode⁢ active⁢ material). According to the technique of the present disclosure, the internal resistance of a battery can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view showing a schematic configuration of a coated active material according to Embodiment 1. FIG. 2 is a cross-sectional view showing a schematic configuration of a positive electrode material according to Embodiment 2. FIG. 3 is a cross-sectional view showing a schematic configuration of a battery according to Embodiment 3. DETAILED DESCRIPTION (Findings on which the Present Disclosure is Based) In a battery using a solid electrolyte, oxygen may be generated from a positive electrode active material due to a side reaction between the positive electrode active material and the solid electrolyte, for example, at the last stage of charging or the like. The generated oxygen oxidizes the solid electrolyte and increases the internal resistance of the battery. The increase in internal resistance causes various problems such as a decrease in output voltage, heat generation in the battery, and a decrease in discharge capacity. Therefore, there is a need for a technology suitable for reducing the internal resistance of a battery using a solid electrolyte. Embodiments of the present disclosure are described below with reference to the drawings. The present disclosure is not limited to the following embodiments. Embodiment 1 FIG. 1 is a cross-sectional view showing a schematic configuration of a coated active material according to Embodiment 1. A coated active material 100 includes a positive electrode active material 101 and a coating layer 102. The coating layer 102 includes a first solid electrolyte. The coating layer 102 coats at least a portion of the surface of the positive electrode active material 101. The coating layer 102 may coat only a portion of the surface of the positive electrode active material 101 or may uniformly coat the surface of the positive electrode active material 101. In the coating layer 102, the first solid electrolyte contains Li, Ti, M, and X. M is at least one element selected from the group consisting of metalloid elements and metal elements other than Li and Ti. X is at least one selected from the group consisting of F, Cl, Br, and I. In the coated active material 100, a quotient obtained by dividing the ratio (%) of the mass of the first solid electrolyte to the total mass of the positive electrode active material 101 and the first solid electrolyte by the specific surface area (m2/g) of the positive electrode active material 101, which is determined by the following mathematical expression (A), is 1.9 or more and 6.9 or less. {(mass of first solid electrolyte)/(total mass of positive electrode active material and first solid electrolyte)}×100/(specific surface area of positive electrode active material)  Mathematical expression (A): Hereinafter, the ratio of the mass of the first solid electrolyte to the total mass of the positive electrode active material 101 and the first solid electrolyte is sometimes referred to as “ratio M