# US 10,873,082 B2 · Negative electrode active material, negative electrode, lithium ion secondary battery, method of using lithium ion secondary battery, method of producing negative electrode active material, and method of producing lithium ion secondary battery > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,873,082 B2 - Document ID: US10873082B2 - Status: Granted - Kind: B2 - Application number: 16/090,906 - Filed: 2017-05-16 - Published: 2019-04-25 - Granted: 2020-12-22 - Earliest claimed: 2016-07-04 - Assignees: Shin-Etsu Chemical Co., Ltd. - Applicants: Shin-Etsu Chemical Co., Ltd. - Inventors: Takakazu Hirose; Reiko Sakai - Web page: https://patentgrep.com/patent/US10873082B2 ## CPC - H01M 4/5825: {Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines} - C01B 33/113: Silicon oxides; Hydrates thereof {(preparing monoxide by reduction of siliceous material C01B33/182)} - C01B 33/32: Alkali metal silicates ({C01B33/24} , C01B33/26 take precedence) - H01M 4/136: Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy - H01M 4/36: Selection of substances as active materials, active masses, active liquids - H01M 4/366: {as layered products} - H01M 4/48: of inorganic oxides or hydroxides - H01M 4/625: {Carbon or graphite} - H01M 4/66: Selection of materials - H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries - H01M 10/44: Methods for charging or discharging (circuits for charging H02J7/00) - C01P 2002/74: by peak-intensities or a ratio thereof only - C01P 2004/61: Micrometer sized, i.e. from 1-100 micrometer - C01P 2004/62: Submicrometer sized, i.e. from 0.1-1 micrometer - C01P 2004/80: Particles consisting of a mixture of two or more inorganic phases - C01P 2006/40: Electric properties - H01M 2004/021: {Physical characteristics, e.g. porosity, surface area} - H01M 2004/027: {Negative 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 - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} - 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 A negative electrode active material including a negative electrode active material particle; the negative electrode active material particle including a silicon compound shown by SiOx (0.5≤x≤1.6), wherein at least part of the Si4+ contained in the negative electrode active material particle is to be changed to at least one state selected from valence states of Siy+ (y is any of 0, 1, 2, and 3) in occlusion of Li in the negative electrode active material. This provides a negative electrode active material that is capable of increasing battery capacity and improving cycle performance when it is used as a negative electrode active material for a secondary battery. ## Claims ### Claim 1 A negative electrode active material containing a negative electrode active material particle; the negative electrode active material particle comprising a silicon compound shown by SiOx (0.5≤x≤1.6), wherein the negative electrode active material particle contains Si4+, and at least part of the Si4+ is configured to be changed to at least one state selected from valence states of Siy+ (y is any of 0, 1, 2, and 3) in occlusion of Li in the negative electrode active material, and the Siy+ include Siz+ (z is any of 1, 2, and 3) in a form of a Li compound after the occlusion of Li in the negative electrode active material. ### Claim 2 (depends on 1) The negative electrode active material according to claim 1, wherein the negative electrode active material particle is the one to form a state of Si0+ by occlusion and release of Li in the negative electrode active material. ### Claim 3 (depends on 2) The negative electrode active material according to claim 2, wherein the Si0+ is amorphous Si. ### Claim 4 (depends on 1) The negative electrode active material according to claim 1, wherein the negative electrode active material has at least one kind of shoulder peak in a range of an energy more than 1841 eV and 1845 eV or less in a XANES spectrum obtained by XANES measurement performed such that a first secondary battery having a negative electrode containing the negative electrode active material and a positive electrode containing a positive electrode active material is subjected to 100 cycles of charging and discharging, followed by disassembling the first secondary battery subjected to the charging and discharging, and producing a second secondary battery having the negative electrode subjected to the charging and discharging together with a counter electrode composed of metallic Li to set the second secondary battery to have an open-circuit potential of 2.0 V, and then the negative electrode is taken out from the second secondary battery and subjected to the XANES measurement. ### Claim 5 (depends on 1) The negative electrode active material according to claim 1, wherein the Siy+ include Siz+ (z is any of 1, 2, and 3), and the Si4+ and the Siz+ are to be reversibly changed to each other in the negative electrode active material particle in repeating of occlusion and release of Li in the negative electrode active material. ### Claim 6 (depends on 1) The negative electrode active material according to claim 1, wherein the negative electrode active material particle has a median diameter of 0.5 μm or more and 20 μm or less. ### Claim 7 (depends on 1) The negative electrode active material according to claim 1, wherein the negative electrode active material particle has a surface layer portion containing a carbon material. ### Claim 8 (depends on 7) The negative electrode active material according to claim 7, wherein the average thickness of the carbon material is 5 nm or more and 5000 nm or less. ### Claim 9 (depends on 1) A negative electrode comprising the negative electrode active material according to claim 1. ### Claim 10 (depends on 9) The negative electrode according to claim 9, further comprising: a negative electrode active material layer containing the negative electrode active material, and a negative electrode current collector, wherein the negative electrode active material layer is formed on the negative electrode current collector, and the negative electrode current collector contains carbon and sulfur, and each content is 100 ppm by mass or less. ### Claim 11 (depends on 9) A lithium ion secondary battery, comprising the negative electrode according to claim 9 as a negative electrode. ### Claim 12 (depends on 11) A method of using the lithium ion secondary battery according to claim 11, comprising: setting a final voltage of the lithium ion secondary battery so as to use the negative electrode in a range of potential lower than the value at an inflection point formed near 0.7 V of a discharge curve obtained from a secondary battery having the negative electrode and a counter electrode composed of metallic Li. ### Claim 13 A method of producing a negative electrode active material containing a negative electrode active material particle, comprising the steps of: preparing negative electrode active material particles each containing a silicon compound shown by a general formula SiOx (0.5≤x≤1.6); and selecting a negative electrode active material particle containing Si4+ in which at least part of the Si4+ is configured to be changed to at least one state selected from valence states of Siy+ (y is any of 0, 1, 2, and 3) in Li occlusion in the negative electrode active material, and the Siy+ include Siz+ (z is any of 1, 2, and 3) in a form of a Li compound after the occlusion of Li in the negative electrode active material. ### Claim 14 (depends on 13) A method of producing a lithium ion secondary battery, comprising: producing a negative electrode using a negative electrode active material produced by the method of producing a negative electrode active material according to claim 13, and producing a lithium ion secondary battery using the produced negative electrode.