# US 2021/0242464 A1 · Negative electrode for lithium-ion secondary battery, and 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 2021/0242464 A1 - Document ID: US20210242464A1 - Status: Published application - Kind: A1 - Application number: 17/232,870 - Filed: 2021-04-16 - Published: 2021-08-05 - Earliest claimed: 2018-10-18 - Assignees: Murata Manufacturing Co., Ltd. - Applicants: Murata Manufacturing Co., Ltd. - Inventors: Naoki HAYASHI - Web page: https://patentgrep.com/patent/US20210242464A1 ## CPC - H01M 4/604: {containing aliphatic main chain polymers} - H01M 4/0433: {Molding} - H01M 4/134: Electrodes based on metals, Si or alloys - H01M 4/366: {as layered products} - H01M 4/386: {Silicon or alloys based on silicon} - H01M 4/583: Carbonaceous material, e.g. graphite-intercalation compounds or CFx - H01M 4/622: {being polymers} - H01M 4/623: {fluorinated polymers} - H01M 4/625: {Carbon or graphite} - H01M 4/661: {Metal or alloys, e.g. alloy coatings (H01M4/669 take precedence)} - H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries - H01M 10/0568: characterised by the solutes - H01M 10/0569: characterised by the solvents - H01M 2004/021: {Physical characteristics, e.g. porosity, surface area} - H01M 2004/027: {Negative electrodes} - H01M 2004/028: {Positive electrodes} - H01M 2300/0025: Organic electrolyte - 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 A lithium-ion secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The negative electrode includes first negative electrode active material particles. The first negative electrode active material particles each include a center part and a covering part. The center part includes a silicon-containing material. The covering part is provided on a surface of the center part and includes a first compound and a second compound. The first compound includes at least one of polyacrylate or polyacrylamide. The second compound includes at least one of polyvinyl alcohol or polyvinyl acetal. ## Claims ### Claim 1 A lithium-ion secondary battery comprising: a positive electrode; a negative electrode including first negative electrode active material particles; and an electrolytic solution, wherein the first negative electrode active material particles each include a center part and a covering part, wherein the center part includes a silicon-containing material, and the covering part is provided on a surface of the center part and includes a first compound and a second compound, and wherein the first compound includes at least one of polyacrylate or polyacrylamide, and the second compound includes at least one of polyvinyl alcohol or polyvinyl acetal. ### Claim 2 (depends on 1) The lithium-ion secondary battery according to claim 1, wherein the negative electrode includes a composite particle including two or more of the first negative electrode active material particles in close contact with each other. ### Claim 3 (depends on 1) The lithium-ion secondary battery according to claim 1, wherein the polyacrylate includes at least one of lithium polyacrylate, sodium polyacrylate, or potassium polyacrylate, and the polyvinyl acetal includes at least one of polyvinyl formal or polyvinyl butyral. ### Claim 4 (depends on 2) The lithium-ion secondary battery according to claim 2, wherein the polyacrylate includes at least one of lithium polyacrylate, sodium polyacrylate, or potassium polyacrylate, and the polyvinyl acetal includes at least one of polyvinyl formal or polyvinyl butyral. ### Claim 5 (depends on 1) The lithium-ion secondary battery according to claim 1, wherein a content of the first compound in the covering part is from 0.1 weight percent to 10 weight percent, and a content of the second compound in the covering part is from 0.1 weight percent to 10 weight percent. ### Claim 6 (depends on 2) The lithium-ion secondary battery according to claim 2, wherein a content of the first compound in the covering part is from 0.1 weight percent to 10 weight percent, and a content of the second compound in the covering part is from 0.1 weight percent to 10 weight percent. ### Claim 7 (depends on 3) The lithium-ion secondary battery according to claim 3, wherein a content of the first compound in the covering part is from 0.1 weight percent to 10 weight percent, and a content of the second compound in the covering part is from 0.1 weight percent to 10 weight percent. ### Claim 8 (depends on 1) The lithium-ion secondary battery according to claim 1, wherein the covering part further includes an electrically conductive substance. ### Claim 9 (depends on 8) The lithium-ion secondary battery according to claim 8, wherein the electrically conductive substance includes at least one of a carbon nanotube, a single-walled carbon nanotube, a carbon nanofiber, carbon black, or acetylene black. ### Claim 10 (depends on 8) The lithium-ion secondary battery according to claim 8, wherein a content of the electrically conductive substance in the covering part is from 0.001 weight percent to 20 weight percent. ### Claim 11 (depends on 1) The lithium-ion secondary battery according to claim 1, wherein the negative electrode further includes second negative electrode active material particles, and the second negative electrode active material particles each include a carbon-containing material. ### Claim 12 (depends on 11) The lithium-ion secondary battery according to claim 11, wherein a proportion of a weight of the first negative electrode active material particles to a sum total of the weight of the first negative electrode active material particles and a weight of the second negative electrode active material particles is greater than or equal to 10 weight percent and less than 100 weight percent. ### Claim 13 A negative electrode for a lithium-ion secondary battery, the negative electrode comprising first negative electrode active material particles each including a center part and a covering part, the center part including a silicon-containing material, the covering part being provided on a surface of the center part and including a first compound and a second compound, the first compound including at least one of polyacrylate or polyacrylamide, the second compound including at least one of polyvinyl alcohol or polyvinyl acetal.