# US 12,002,950 B2 · Cathode active material for lithium secondary battery and method of manufacturing the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,002,950 B2 - Document ID: US12002950B2 - Status: Granted - Kind: B2 - Application number: 17/475,058 - Filed: 2021-09-14 - Published: 2021-12-30 - Granted: 2024-06-04 - Earliest claimed: 2018-11-06 - Assignees: SK On Co., Ltd. - Applicants: SK Innovation Co., Ltd. - Inventors: Jik Soo Kim; Sang Bok Kim; Hyo Shin Kwak; Myoung Lae Kim; Se Rah Moon; Jin Seok Seo; Mi Jung Noh; Duck Chul Hwang - Web page: https://patentgrep.com/patent/US12002950B2 ## CPC - H01M 4/366: {as layered products} - C07D 277/36: Sulfur atoms - C07D 295/14: substituted by carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals - H01M 4/1391: of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx - H01M 4/525: of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy - H01M 4/62: Selection of inactive substances as ingredients for active masses, e.g. binders, fillers - H01M 4/628: {Inhibitors, e.g. gassing inhibitors, corrosion inhibitors} - H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries - H01M 2004/028: {Positive 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 - C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08) - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A cathode active material for a lithium secondary battery includes a lithium metal oxide particle and a thio-based compound formed on at least portion of a surface of the lithium metal oxide particle. The thio-based compound has a double bond that contains a sulfur atom. Chemical stability of the lithium metal oxide particle may be improved and surface residues may be reduced by the thio-based compound. ## Claims ### Claim 1 A cathode active material for a lithium secondary battery, comprising: a lithium metal oxide particle; and a thiosulfate anion (S2O32−) formed on at least portion of a surface of the lithium metal oxide particle, wherein a content of the thiosulfate anion of the lithium metal oxide particle measured by an ion chromatography analysis is in a range from 100 ppb to 8,000 ppb. ### Claim 2 (depends on 1) The cathode active material for a lithium secondary battery according to claim 1, wherein the content of the thiosulfate anion is measured using an extraction solution obtained by filtering a solution obtained by mixing the cathode active material for 3 hours at room temperature using a Na2CO3 buffer solution. ### Claim 3 (depends on 1) The cathode active material for a lithium secondary battery according to claim 1, wherein the content of the thiosulfate anion is in a range from 400 ppb to 5,000 ppb. ### Claim 4 (depends on 1) The cathode active material for a lithium secondary battery according to claim 1, wherein a surface component represented by General Formula 2 is detected by a Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS) analysis on the surface the lithium metal oxide particle: M1xCyHzSaOb [General Formula 2] wherein, in the General Formula 2 above, M1 is an alkali metal or an alkali earth metal, x≥0, y≥0, z≥0, a>0 and b>0. ### Claim 5 (depends on 1) The cathode active material for a lithium secondary battery according to claim 1, wherein the lithium metal oxide particle includes a nickel-based lithium oxide represented by General Formula 1 below: LxNiyM1-yO2 [General Formula 1] wherein, in the General Formula 1 above, 0.95≤x≤1.08, y≥0.5, and M is at least one element selected from a group consisting of Co, Mn, Al, Zr, Ti, B, Mg or Ba. ### Claim 6 (depends on 5) The cathode active material for a lithium secondary battery according to claim 5, wherein, in the General Formula 1, 0.8≤y≤0.93. ### Claim 7 (depends on 1) The cathode active material for a lithium secondary battery according to claim 1, wherein the lithium metal oxide particle includes a doping or a coating which contains at least one of Al, Zr or Ti. ### Claim 8 (depends on 1) The cathode active material for a lithium secondary battery according to claim 1, wherein the thiosulfate anion is directly bonded to the surface of the lithium metal oxide particle. ### Claim 9 A method of preparing a cathode active material for a lithium secondary battery, comprising: preparing a preliminary lithium metal oxide particle; cleaning the preliminary lithium metal oxide particle using a washing solution that includes a thiosulfate anion (S2O32−) salt; and drying or annealing the washed preliminary lithium metal oxide particle to obtain a lithium metal oxide particle including a thiosulfate anion formed on at least portion of a surface thereof; wherein a content of the thiosulfate anion of the lithium metal oxide particle including a thiosulfate anion measured by an ion chromatography analysis is in a range from 100 ppb to 8,000 ppb. ### Claim 10 (depends on 9) The method according to claim 9, wherein an amount of the thiosulfate anion (S2O32−) salt is in a range from about 0.1 wt % to about 2 wt % based on a total weight of the washing solution. ### Claim 11 (depends on 9) The method according to claim 9, wherein cleaning the preliminary lithium metal oxide particle includes a first washing treatment and a second washing treatment, and an active material cake is formed by the first washing treatment. ### Claim 12 (depends on 11) The method according to claim 11, wherein the second washing treatment includes providing the washing solution to flow through the active material cake without stirring. ### Claim 13 (depends on 11) The method according to claim 11, wherein an amount of the thiosulfate anion (S2O32−) salt in the washing solution used in the first washing treatment is greater than an amount of the thiosulfate anion (S2O32−) salt in the washing solution used in the second washing treatment. ### Claim 14 (depends on 1) A lithium secondary battery, comprising: a cathode including a cathode active material according to claim 1; an anode; and a separation layer interposed between the cathode and the anode.