# US 12,119,481 B2 · Negative electrode active material for secondary batteries and secondary battery > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,119,481 B2 - Document ID: US12119481B2 - Status: Granted - Kind: B2 - Application number: 17/267,231 - Filed: 2019-08-23 - Published: 2021-06-03 - Granted: 2024-10-15 - Earliest claimed: 2018-08-30 - Assignees: Panasonic Intellectual Property Management Co., Ltd. - Applicants: Panasonic Intellectual Property Management Co., Ltd. - Inventors: Yohei Uchiyama; Norihisa Yamamoto; Keita Okazaki - Web page: https://patentgrep.com/patent/US12119481B2 ## CPC - H01M 4/1397: of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy - H01M 4/364: {as mixtures} - H01M 4/136: Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy - H01M 4/366: {as layered products} - H01M 4/386: {Silicon or alloys based on silicon} - H01M 4/485: of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy (H01M4/505, H01M4/525 take precedence) - H01M 4/5825: {Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines} - H01M 4/62: Selection of inactive substances as ingredients for active masses, e.g. binders, fillers - H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries - 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 A negative electrode active material for a secondary battery includes silicate composite particles each of which contain a silicate phase and silicon particles dispersed in the silicate phase, the silicate phase is an oxide phase containing Si, O, and alkali metals, the alkali metals include at least Na and Li, and an atomic ratio: Na/Li of Na to Li is 0.1 to 7.1. ## Claims ### Claim 1 A negative electrode active material for a secondary battery, comprising: silicate composite particles each of which contain a silicate phase and silicon particles dispersed in the silicate phase, wherein the silicate phase is an oxide phase which contains Si, O, and alkali metals, the alkali metals include at least Na and Li, and an atomic ratio: Na/Li of Na to Li is 0.1 to 7.1, wherein the silicate phase further contains Ca, wherein, in a cross-sectional SEM-EDX analysis of the negative electrode active material, a ratio: I(Ca/O) of an intensity which belongs to Ca to an intensity which belongs to O is 0.5 or less. ### Claim 2 (depends on 1) The negative electrode active material according to claim 1, wherein, with respect to a total amount of elements other than O contained in the silicate phase, a content of Na is 7 percent by mole or more, a content of Li is 7 percent by mole or more, and a total content of Li and Na is 70 percent by mole or less. ### Claim 3 (depends on 1) The negative electrode active material according to claim 1, wherein the silicate phase further contains a group 2 element, and a content of the group 2 element with respect to a total amount of elements other than O contained in the silicate phase is 20 percent by mole or less. ### Claim 4 (depends on 1) The negative electrode active material according to claim 1, wherein the silicate phase further contains an element M, and the element M is at least one selected from the group consisting of B, Al, Zr, Nb, Ta, La, V, Y, Ti, P, Bi, Zn, Sn, Pb, Sb, Co, Er, F, and W. ### Claim 5 (depends on 1) The negative electrode active material according to claim 1, wherein, in an X-ray diffraction pattern of the silicate composite particles, a ratio of an integrated value of a diffraction peak of each of all the other elements to an integrated value of a diffraction peak which belongs to the (111) plane of single Si is 0.5 or less. ### Claim 6 (depends on 1) The negative electrode active material according to claim 1, wherein the silicate composite particles have a void rate of less than 5 percent by volume. ### Claim 7 (depends on 1) A secondary battery comprising: a positive electrode; a negative electrode; an electrolyte; and a separator provided between the positive electrode and the negative electrode, wherein the negative electrode includes a collector and a negative electrode active material layer, and the negative electrode active material layer contains the negative electrode active material according to claim 1. ### Claim 8 (depends on 7) The secondary battery according to claim 7, wherein, in a cross-sectional SEM-EDX analysis of the negative electrode active material layer in a discharge state, a ratio: I(Na/O) of an intensity which belongs to Na to an intensity which belongs to O is 0.02 to 0.7. ### Claim 9 A secondary battery comprising: a positive electrode; a negative electrode; an electrolyte; and a separator provided between the positive electrode and the negative electrode, wherein the negative electrode includes a collector and a negative electrode active material layer, and the negative electrode active material layer contains a negative electrode active material comprising: silicate composite particles each of which contain a silicate phase and silicon particles dispersed in the silicate phase, wherein the silicate phase is an oxide phase which contains Si, O, and alkali metals, the alkali metals include at least Na and Li, and an atomic ratio: Na/Li of Na to Li is 0.1 to 7.1, wherein the silicate phase further contains Ca, wherein, in a cross-sectional SEM-EDX analysis of the negative electrode active material layer in a discharge state, a ratio: I(Ca/O) of an intensity which belongs to Ca to an intensity which belongs to O is 0.5 or less.