# US 10,483,531 B2 · Negative electrode active material for nonaqueous electrolyte secondary batteries > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,483,531 B2 - Document ID: US10483531B2 - Status: Granted - Kind: B2 - Application number: 14/412,854 - Filed: 2013-07-08 - Published: 2015-07-09 - Granted: 2019-11-19 - Earliest claimed: 2012-07-06 - Assignees: Mitsui Mining & Smelting Co., Ltd. - Applicants: Mitsui Mining & Smelting Co., Ltd. - Inventors: Daisuke Inoue; Yanko Marinov Todorov; Shinya Kagei - Web page: https://patentgrep.com/patent/US10483531B2 ## CPC - H01M 4/366: {as layered products} - H01M 4/134: Electrodes based on metals, Si or alloys - H01M 4/364: {as mixtures} - H01M 4/386: {Silicon or alloys based on silicon} - H01M 4/583: Carbonaceous material, e.g. graphite-intercalation compounds or CFx - H01M 4/587: for inserting or intercalating light metals - H01M 4/622: {being polymers} - H01M 4/625: {Carbon or graphite} - H01M 4/626: {Metals} - H01M 10/052: Li-accumulators - H01M 2220/20: Batteries in motive systems, e.g. vehicle, ship, plane - H01M 2220/30: Batteries in portable systems, e.g. mobile phone, laptop - Y02E 60/10: Energy storage using batteries - Y02T 10/70: Energy storage systems for electromobility, e.g. 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 - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract Proposed is a novel negative electrode for nonaqueous electrolyte secondary batteries in which the battery capacity does not decrease even when charging and discharging are repeated. Proposed is a silicon-containing negative electrode active material for nonaqueous electrolyte secondary batteries, comprising negative electrode active material particles which are provided with a surface layer containing carbon and titanium or aluminum on the entirety or a portion of the surface of the active material. ## Claims ### Claim 1 A silicon-containing negative electrode active material for nonaqueous electrolyte secondary batteries, wherein the negative electrode active material particles comprise a surface layer comprising carbon and titanium or aluminum on an entirety or a portion of a surface of a core portion, wherein the core portion comprises: pure silicon; a silicon alloy selected from SiB4 or SiB6, Cu5Si, FeSi2, or Mg2Si; or a silicon compound selected from Si3N4 or SiC in an amount of 90% by mass or more, and a content of titanium or aluminum in the surface layer is 0.002 to 0.07% by mass of the silicon-containing negative electrode active material particles. ### Claim 2 (depends on 1) The silicon-containing negative electrode active material for nonaqueous electrolyte secondary batteries according to claim 1, wherein a content of carbon in the surface layer is 0.004 to 0.5% by mass of the silicon-containing negative electrode active material particles. ### Claim 3 (depends on 1) The silicon-containing negative electrode active material for nonaqueous electrolyte secondary batteries according to claim 1, wherein said surface layer is formed from an organic compound comprising carbon and titanium or aluminum, which is a coupling agent containing the titanium or aluminum. ### Claim 4 (depends on 3) The silicon-containing negative electrode active material for nonaqueous electrolyte secondary batteries according to claim 3, wherein said negative electrode active material particles are subjected to heating at 300 to 500° C. ### Claim 5 (depends on 3) The silicon-containing negative electrode active material for nonaqueous electrolyte secondary batteries according to claim 3, wherein said coupling agent containing titanium or aluminum further has an amino group at a side chain. ### Claim 6 (depends on 1) The silicon-containing negative electrode active material for nonaqueous electrolyte secondary batteries according to claim 1, wherein D50 measured by a laser diffraction scattering type particle size distribution measurement method is 0.1 μm to 5.0 μm. ### Claim 7 (depends on 1) A negative electrode for nonaqueous electrolyte secondary batteries, comprising the active material for nonaqueous electrolyte secondary batteries according to claim 1, and a binder. ### Claim 8 (depends on 1) A negative electrode for nonaqueous electrolyte secondary batteries, comprising the active material for nonaqueous electrolyte secondary batteries according to claim 1 as a first negative electrode active material, a graphite as a second negative electrode active material, and a binder. ### Claim 9 (depends on 7) The negative electrode for nonaqueous electrolyte secondary batteries according to claim 7, wherein the binder is a polyimide. ### Claim 10 (depends on 7) A nonaqueous electrolyte secondary battery comprising the negative electrode according to claim 7. ### Claim 11 (depends on 8) A nonaqueous electrolyte secondary battery comprising the negative electrode according to claim 8. ### Claim 12 (depends on 9) A nonaqueous electrolyte secondary battery comprising the negative electrode according to claim 9. ### Claim 13 (depends on 1) The silicon-containing negative electrode active material for nonaqueous electrolyte secondary batteries according to claim 1, wherein a content of the carbon in the surface layer is 0.004 to 0.5% by mass. ### Claim 14 (depends on 1) The silicon-containing negative electrode active material for nonaqueous electrolyte secondary batteries according to claim 1, wherein said surface layer is formed from an organic compound comprising carbon and titanium or aluminum, which is a coupling agent containing the titanium or aluminum. ### Claim 15 (depends on 2) The silicon-containing negative electrode active material for nonaqueous electrolyte secondary batteries according to claim 2, wherein said surface layer is formed from an organic compound comprising carbon and titanium or aluminum, which is a coupling agent containing the titanium or aluminum. ### Claim 16 (depends on 14) The silicon-containing negative electrode active material for nonaqueous electrolyte secondary batteries according to claim 14, wherein said negative electrode active material particles are subjected to heating at 300 to 500° C. ### Claim 17 (depends on 15) The silicon-containing negative electrode active material for nonaqueous electrolyte secondary batteries according to claim 15, wherein said negative electrode active material particles are subjected to heating at 300 to 500° C. ### Claim 18 (depends on 4) The silicon-containing negative electrode active material for nonaqueous electrolyte secondary batteries according to claim 4, wherein said coupling agent containing titanium or aluminum further has an amino group at a side chain. ### Claim 19 (depends on 8) The negative electrode for nonaqueous electrolyte secondary batteries according to claim 8, wherein the binder is a polyimide. ### Claim 20 (depends on 1) The negative electrode active material for nonaqueous electrolyte secondary batteries according to claim 1, wherein the surface layer containing the carbon and the titanium or aluminum is provided as the outermost layer of the core portion. ### Claim 21 (depends on 1) The negative electrode active material for nonaqueous electrolyte secondary batteries according to claim 1, wherein the total content of iron (Fe), calcium (Ca), phosphorus (P), and oxygen (O) in the negative electrode active material is from 0.1 to 2.5% by mass. ### Claim 22 (depends on 1) The silicon-containing negative electrode active material for nonaqueous electrolyte secondary batteries according to claim 1, wherein the negative electrode active material particles are materials in which the additive elements are solid-solubilized in one of the silicon-containing materials, as a silicon solid solution.