# US 2021/0344002 A1 · Lithium Secondary Battery > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0344002 A1 - Document ID: US20210344002A1 - Status: Published application - Kind: A1 - Application number: 16/973,201 - Filed: 2020-01-23 - Published: 2021-11-04 - Earliest claimed: 2019-01-24 - Assignees: LG Chem, Ltd. - Applicants: LG Chem, Ltd. - Inventors: Do Hwa Jung; Tae Gyun Noh; Ki Woong Kim; Woo Sirl Lee; Yoon Jae Lee; Jung Whan Song - Web page: https://patentgrep.com/patent/US20210344002A1 ## CPC - H01M 4/364: {as mixtures} - 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 4/587: for inserting or intercalating light metals - H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries - H01M 10/0567: characterised by the additives - H01M 2300/004: Three solvents - 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 provides a lithium secondary battery which includes a positive electrode including a first lithium cobalt oxide and a second lithium cobalt oxide which have different average particle diameters (D50) from each other, a negative electrode including first graphite and second graphite which have different average particle diameters (D50) from each other, and an electrolyte including a first additive as a nitrile-based compound, wherein the first lithium cobalt oxide and the second lithium cobalt oxide each independently contain aluminum in a concentration of 2,500 ppm to 4,000 ppm. ## Claims ### Claim 1 A lithium secondary battery comprising: a positive electrode including a first lithium cobalt oxide and a second lithium cobalt oxide, wherein the first lithium cobalt oxide and the second lithium cobalt oxide have different average particle diameters (D50) from each other; a negative electrode including first graphite and second graphite, wherein the first graphite and the second graphite have different average particle diameters (D50) from each other; and an electrolyte including a first additive comprising a nitrile-based compound, wherein the first lithium cobalt oxide and the second lithium cobalt oxide each independently contain aluminum in a concentration of 2,500 ppm to 4,000 ppm. ### Claim 2 (depends on 1) The lithium secondary battery of claim 1, wherein the first lithium cobalt oxide has an average particle diameter (D50) of 1 μm to 4 μm, and the second lithium cobalt oxide has an average particle diameter (D50) of 5 μm to 15 μm. ### Claim 3 (depends on 1) The lithium secondary battery of claim 1, wherein the first graphite has an average particle diameter (D50) of 5 μm to 14 μm, and the second graphite has an average particle diameter (D50) of 15 μm to 25 μm. ### Claim 4 (depends on 1) The lithium secondary battery of claim 1, wherein the first graphite and the second graphite are artificial graphite. ### Claim 5 (depends on 1) The lithium secondary battery of claim 1, wherein the electrolyte comprises a lithium salt in a concentration of 1.0 M to 1.5 M. ### Claim 6 (depends on 1) The lithium secondary battery of claim 1, wherein the first additive is included in an amount of 2 parts by weight to 10 parts by weight based on 100 parts by weight of the electrolyte. ### Claim 7 (depends on 1) The lithium secondary battery of claim 1, wherein the first additive comprises at least one nitrile-based compound selected from the group consisting of succinonitrile, adiponitrile, butyronitrile, pimelonitrile, and hexanetricarbonitrile. ### Claim 8 (depends on 1) The lithium secondary battery of claim 1, wherein the electrolyte further comprises a second additive, wherein the second additive comprises at least one selected from the group consisting of a cyclic sultone-based compound and a fluorine-substituted or unsubstituted cyclic carbonate-based compound. ### Claim 9 (depends on 8) The lithium secondary battery of claim 8, wherein the second additive is included in an amount of 10 parts by weight to 15 parts by weight based on 100 parts by weight of the electrolyte. ### Claim 10 (depends on 1) The lithium secondary battery of claim 1, wherein an operating voltage of the lithium secondary battery is in a range of 4.2 V to 4.5 V. ### Claim 11 (depends on 1) The lithium secondary battery of claim 1, wherein the first lithium cobalt oxide has an average particle diameter (D50) of 2 μm to 3 μm, and the second lithium cobalt oxide has an average particle diameter (D50) of 10 μm to 12 μm. ### Claim 12 (depends on 1) The lithium secondary battery of claim 1, wherein the first graphite has an average particle diameter (D50) of 10 μm to 12 μm, and the second graphite has an average particle diameter (D50) of 19 μm to 22 μm. ### Claim 13 (depends on 4) The lithium secondary battery of claim 4, wherein the artificial graphite has a round shape. ### Claim 14 (depends on 8) The lithium secondary battery of claim 8, wherein the cyclic sultone-based compound is at least one selected from 1,3-propane sultone (PS) or 1,3-propene sultone (PRS), and the fluorine-substituted or unsubstituted cyclic carbonate-based compound is at least one selected from fluoroethylene carbonate (FEC), vinylene carbonate (VC), or vinylethylene carbonate (VEC). ### Claim 15 (depends on 8) The lithium secondary battery of claim 8, wherein the electrolyte further comprises at least one additional additive selected from ethylene sulfate (Esa), trimethylene sulfate (TMS), ethylene glycol bis(2-cyanoethyl) ether (EGPN), lithium difluoro(oxalato)borate (LIDFOB), lithium difluorophosphate, lithium oxalyldifluoroborate, or LiBF4.