# US 11,909,036 B2 · Silicon/carbon composite material with highly compact structure, method for preparing same, and use thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,909,036 B2 - Document ID: US11909036B2 - Status: Granted - Kind: B2 - Application number: 17/489,770 - Filed: 2021-09-29 - Published: 2022-10-06 - Granted: 2024-02-20 - Earliest claimed: 2021-04-01 - Assignees: Guangdong Kaijin New Energy Technology Co., Ltd. - Applicants: Guangdong Kaijin New Energy Technology Co., Ltd. - Inventors: Anhua Zheng; Dexin Yu; Yongjun Yang - Web page: https://patentgrep.com/patent/US11909036B2 ## CPC - H01M 4/364: {as mixtures} - 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 4/587: for inserting or intercalating light metals - H01M 4/625: {Carbon or graphite} - H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries - H01M 10/052: Li-accumulators - 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 - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract The present invention relates to the field of anode materials of lithium batteries, and in particular, relates to a silicon/carbon composite material with a highly compact structure. The silicon/carbon composite material with the highly compact structure includes silicon particles and a carbon coating layer, and further includes a highly compact carbon matrix, wherein the silicon particles are distributed inside the highly compact carbon matrix evenly and dispersively and forms an inner core; and the silicon/carbon composite with the highly compact structure is compact inside without voids or has few closed voids inside. The present invention provides the silicon/carbon composite material with the highly compact structure with a reduced volumetric expansion effect and an improved cycle performance, a method for preparing the same, and a use thereof. ## Claims ### Claim 1 A silicon/carbon composite material with a compact structure, comprising an inner core and a carbon coating layer coated on the inner core, wherein the inner core comprises a compact carbon matrix and silicon particles distributed inside the compact carbon matrix evenly and dispersively, and the silicon/carbon composite material is compact inside without voids or has closed voids therein with a volume ratio of 0-10%; wherein the silicon/carbon composite material has a true density of 1.90-2.64 g/cm3, and has an oxygen content of 0-10%, a carbon content of 20-90% and a silicon content of 5-90%. ### Claim 2 (depends on 1) The silicon/carbon composite material according to claim 1, wherein the silicon/carbon composite material has a porosity of 0-10%, and a particle size D50, of 2-30 μm. ### Claim 3 (depends on 1) The silicon/carbon composite material according to claim 1, wherein the silicon particles are one or both of nano-silicon and nano-silicon oxide (SiOx), the nano-silicon has a particle size D50 of 1-100 nm, and a grain size of 1-10 nm; and X in the SiOx is 0-0.8. ### Claim 4 (depends on 1) The silicon/carbon composite material according to claim 1, wherein when the silicon/carbon composite material has closed voids inside, the closed voids have a pore size of 3-50 nm. ### Claim 5 (depends on 1) A method for preparing a silicon/carbon composite material with a compact structure according to claim 1, comprising: placing a matrix in a reactor, and depositing silicon particles and a compact carbon matrix on the matrix by synchronous or alternate vapor deposition under a protective atmosphere to obtain a precursor A of a compact structure; separating the precursor A from the matrix, and crushing the precursor A to obtain a silicon/carbon composite material precursor B; performing carbon coating on the silicon carbon composite material precursor B to obtain a silicon/carbon composite material precursor C; and sintering the silicon/carbon composite material precursor C at high temperature to obtain the silicon/carbon composite material with the compact structure. ### Claim 6 (depends on 5) The method for preparing the silicon/carbon composite material according to claim 5, wherein the precursor A of the compact structure is powder particles or blocks, and has a porosity of 0-10%. ### Claim 7 (depends on 5) The method for preparing the silicon/carbon composite material according to claim 5, wherein the matrix is one or more of a piece of graphite paper, carbon foam, a metal bar, a metal plate, the silicon/carbon composite material with the compact structure prepared with the method, and the precursor B. ### Claim 8 (depends on 5) The method for preparing the silicon/carbon composite material according to claim 5, wherein the silicon/carbon composite material with the compact structure has an initial reversible capacity not less than 1800 mAh/g, and has an expansion rate less than 40% and a capacity retention rate more than 95% after 50 cycles. ### Claim 9 A silicon/carbon composite material with a compact structure, comprising an inner core and a carbon coating layer coated on the inner core, wherein the inner core comprises a compact carbon matrix and silicon particles distributed inside the compact carbon matrix evenly and dispersively, and the silicon/carbon composite material is compact inside without voids or has closed voids therein with a volume ratio of 0-10%; wherein the silicon particles are one or both of nano-silicon and nano-silicon oxide (SiOx), the nano-silicon has a particle size D50 of 1-100 nm, and a grain size of 1-10 nm; and X in the SiOx is 0-0.8. ### Claim 10 (depends on 9) The silicon/carbon composite material according to claim 9, wherein the silicon/carbon composite material has a porosity of 0-10%, and a particle size D50 of 2-30 μm. ### Claim 11 (depends on 9) The silicon/carbon composite material according to claim 9, wherein when the silicon carbon composite material has closed voids inside, the closed voids have a pore size of 3-50 nm.