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JP-2026076058-A - Positive electrode material for all-solid-state batteries, all-solid-state battery, and method for manufacturing the positive electrode material for all-solid-state batteries

JP2026076058AJP 2026076058 AJP2026076058 AJP 2026076058AJP-2026076058-A

Abstract

[Problem] Improvement of all-solid-state batteries [Solution] A positive electrode material for an all-solid-state battery comprising a positive electrode active material and a coating material, wherein the positive electrode active material has a composition represented by formula (1-1): Li 2 Co (1-x) P (2-y) M 1 x M 2 y O 7 , and the coating material has a composition represented by formula (2): Li 4 P 2 O 7 , and the coating material is present in a range of more than 0.5% by weight and less than 15.0% by weight relative to the positive electrode active material. [Selection Diagram] Figure 2

Inventors

  • 小野田 識十

Assignees

  • ＦＤＫ株式会社

Dates

Publication Date
20260511
Application Date
20241023

Claims (7)

  1. It comprises a positive electrode active material and a coating material, The above positive electrode active material has a composition represented by the following formula (1-1), Li 2 Co (1-x) P (2-y) M 1 x M 2 y O 7 ...(1-1) (In formula (1), M1 is one or more metallic elements selected from titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), and nickel (Ni). M2 is one or more nonmetallic and/or metallic elements selected from boron (B), aluminum (Al), gallium (Ga), carbon (C), silicon (Si), and germanium (Ge). x and y are numbers that satisfy 0 ≤ x < 1 and 0 ≤ y ≤ 0.07. The above coating material has a composition represented by formula (2): Li 4 P 2 O 7 , The above coating material is present in an amount greater than 0.5% by weight and less than 15.0% by weight relative to the above positive electrode active material. Cathode material for all-solid-state batteries.
  2. The positive electrode material according to claim 1 , wherein the positive electrode active material has a composition represented by formula ( 1-2 ): Li₂CoP₂Oₙ .
  3. The positive electrode material according to claim 1, wherein the coating material is present in an amount of 0.7% to 10% by weight relative to the positive electrode active material.
  4. A solid-state battery comprising a positive electrode layer containing the positive electrode material described in claim 1.
  5. The following steps 1, 2, and 3 are included: Step 1: A step in which a water-soluble lithium salt, a water-soluble phosphate, a complexing agent, and water are mixed to prepare an aqueous solution of the raw materials for the coating material. Step 2: A step in which the aqueous solution obtained in Step 1 is brought into contact with the positive electrode active material to prepare the positive electrode material precursor. Step 3: A step in which the cathode material precursor obtained in Step 2 is calcined to obtain a cathode material for an all-solid-state battery that includes a cathode active material and a coating material. The above positive electrode active material has a composition represented by the following formula (1-1), Li 2 Co (1-x) P (2-y) M 1 x M 2 y O 7 ...(1-1) (In formula (1), M1 is one or more metallic elements selected from titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), and nickel (Ni). M2 is one or more nonmetallic and/or metallic elements selected from boron (B), aluminum (Al), gallium (Ga), carbon (C), silicon (Si), and germanium (Ge). x and y are numbers that satisfy 0 ≤ x < 1 and 0 ≤ y ≤ 0.07. The above coating material has a composition represented by formula (2): Li 4 P 2 O 7 , In the above positive electrode material, the coating material is present in an amount greater than 0.5% by weight and less than 15.0% by weight relative to the positive electrode active material. A method for manufacturing positive electrode material for all-solid-state batteries.
  6. The manufacturing method according to claim 5 , wherein the positive electrode active material has a composition represented by formula ( 1-2 ): Li₂CoP₂Oₙ .
  7. The manufacturing method according to claim 5, wherein the positive electrode material contains the coating material in an amount of 0.7% to 10% by weight relative to the positive electrode active material.

Description

This invention relates to a positive electrode material. Specifically, this invention relates to a positive electrode material for all-solid-state batteries, an all-solid-state battery using the same, and a method for manufacturing the positive electrode material for the all-solid-state battery. Lithium-ion batteries are widely used in electronic devices and automobiles, and represent a large global market. Various next-generation products are being proposed to improve the performance and safety of lithium-ion batteries. All-solid-state lithium-ion batteries have attracted particular attention in recent years among next-generation lithium-ion batteries due to their expected high safety. While various batteries are known as "solid-state batteries," both theoretically and practically, today the term "all-solid-state battery" narrowly refers to all-solid-state lithium-ion batteries. The main body of an all-solid-state battery is formed from a laminate of a positive electrode active material layer, a solid electrolyte layer, a negative electrode active material layer, and a current collector film. In developing solid-state batteries using the NASICON-type solid electrolyte LAGP, the applicant has conducted extensive research from various angles, including materials such as the NASICON-type solid electrolyte LAGP and positive electrode material, and manufacturing processes (Patent Documents 1, 2, 3, and 4). As described in Non-Patent Documents 1, 2, and 3, one of the problems in the practical application of solid-state batteries is the significant resistance generated at the interface between the electrolyte layer and the electrode layer. To solve this problem, materials that exist between the electrolyte layer and the electrode layer to control interfacial resistance have been proposed (referred to as "interfacial control material" in Non-Patent Document 1, and as "buffer layer" in Non-Patent Documents 2 and 3). As an example of reducing interfacial resistance using such materials, Non-Patent Document 1 describes an example in which a Li-Nb-O system material is formed at the interface of a laminated structure: negative electrode Li / solid electrolyte Li 7 La 3 Zr 2 O 12 / positive electrode active material LiCoO 2. Non-Patent Documents 2 and 3 describe an example in which a nanometer-order buffer layer made of Li 4 Ti 5 O 12 is formed on the surface of the positive electrode active material LiCoO 2 . On the other hand, the applicant succeeded in forming a Li4P2O7 layer on the surface of a pyrophosphate-based positive electrode active material to suppress the reaction between the positive electrode active material and the solid electrolyte during the heat treatment when manufacturing the electrode layer of an all -solid-state battery (Patent Document 5). The reactivity between this Li4P2O7 layer and the solid electrolyte LAGP is low, and the crystal structure of the positive electrode active material and the solid electrolyte is maintained even after firing. Since the crystal structure of the positive electrode active material having the above Li4P2O7 layer is stable, it can be said that it is less likely to deteriorate during the repeated charging and discharging of the all-solid-state battery. However, the above - mentioned interfacial resistance was not considered here. The relationship between the above Li4P2O7 layer and the above-mentioned interfacial resistance is not mentioned at all in Patent Document 5. "The Cutting Edge of Solid-State Batteries (Popular Edition)," First Printing of the Popular Edition, May 11, 2018, pp. 164-172, ISBN 978-4-7813-1279-8 C3054"Materials Science Series: The Science of Lithium-ion Batteries," First printing July 15, 2010, pp. 207-210, ISBN 978-4-7536-5638-7 C3042"Introduction to Solid-State Batteries," First Edition, First Printing, February 28, 2019, pp. 80-91, ISBN 978-4-526-07939-9 C3054 Patent No. 6622974Patent No. 6931529Japanese Patent Publication No. 2021-51825Japanese Patent Publication No. 2021-185118Patent No. 7274868 Figures 1A to 1C are schematic diagrams showing the configuration of a solid-state battery according to this embodiment.A schematic diagram showing the particles of the positive electrode material of the present invention.Figures 3A to 3E are schematic diagrams illustrating an example of the manufacturing process for positive electrode composite layer parts.Figures 4A to 4C are schematic diagrams showing an example of a fabricated positive electrode mixture layer part.Figures 5A to 5C are schematic diagrams showing an example of a fabricated negative electrode mixture layer part.Figures 6A to 6C are schematic diagrams illustrating an example of the process for manufacturing a solid-state battery body.Figures 7A to 7C are schematic diagrams illustrating an example of the process for manufacturing a solid-state battery body.A graph showing the results of the cycle tests conducted in the examples and comparative examples. [Cathode material for all-soli