# US 8,771,881 B2 · Electrolyte for lithium ion secondary battery and lithium ion secondary battery comprising the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,771,881 B2 - Document ID: US8771881B2 - Status: Granted - Kind: B2 - Application number: 12/255,799 - Filed: 2008-10-22 - Published: 2009-11-26 - Granted: 2014-07-08 - Earliest claimed: 2008-05-21 - Assignees: Samsung SDI Co., Ltd. - Applicants: Jinsung Kim; Narae Park; Jinhyunk Lim; Suhee Han; Jinbum Kim; Jungkang Oh - Inventors: Jinsung Kim; Narae Park; Jinhyunk Lim; Suhee Han; Jinbum Kim; Jungkang Oh - Web page: https://patentgrep.com/patent/US8771881B2 ## CPC - H01M 10/0567: characterised by the additives - H01M 10/0525: Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries - H01M 10/4235: {Safety or regulating additives or arrangements in electrodes, separators or electrolyte (H01M10/4242 takes precedence)} - H01M 10/0569: characterised by the solvents - 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 An electrolyte for a lithium ion secondary battery includes a non-aqueous organic solvent; a lithium salt; and a phosphonitrile fluoride trimer as an additive, and a lithium ion secondary battery comprising the same. The thickness increase rate of a lithium ion secondary battery including the electrolyte is reduced even when the battery is kept at a high temperature. Thus, the thermal stability and durability of the battery are prominently improved. The durability of the battery can be further improved by including a vinylene carbonate or ethylene carbonate group compound in the electrolyte. ## Claims ### Claim 1 An electrolyte for a lithium ion secondary battery comprising: a non-aqueous organic solvent; lithium salt; and a phosphonitrile fluoride trimer represented by a chemical formula 1 below as an additive: wherein the amount of the phosphonitrile fluoride trimer of the chemical formula 1 is 0.1 to 1 parts by weight based on 100 parts by weight of the total electrolyte, wherein the non-aqueous organic solvent comprises at least one selected from the group consisting of a carbonate, an ester, an ether and a ketone, wherein the non-aqueous organic solvent further comprises at least one of benzene, fluorobenzene, bromobenzene, chlorobenzene, toluene, xylene, mesitylene or a mixture thereof, and wherein the electrolyte further comprises at least one selected from the group consisting of vinylene carbonate, propene sultone and an ethylene carbonate group compound represented by a chemical formula 2: where R1 and R2 are respectively selected from the group consisting of hydrogen, a halogen group, a cyano group (CN), a nitro group (NO2), a vinyl group and a fluorinated alkyl group having 1 to 5 carbons, where R1 and R2 are not both hydrogen. ### Claim 2 (depends on 1) The electrolyte of claim 1, wherein the ethylene carbonate group compound is fluoroethylene carbonate. ### Claim 3 (depends on 1) The electrolyte of claim 1, wherein the carbonate is at least one selected from the group of dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, ethylmethyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate and pentylene carbonate. ### Claim 4 (depends on 1) The electrolyte of claim 1, wherein the ester is at least one selected from the group consisting of n-methyl acetate, n-ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, y-butyrolactone, decanolide, valerolactone, mevalonolactone and caprolactone. ### Claim 5 (depends on 1) The electrolyte of claim 1, wherein the ether is at least one selected from the group consisting of dibutyl ether, tetraglyme, diglyme, dimethoxy ethane, 2-methyltetrahydrofuran and tetrahydrofuran. ### Claim 6 (depends on 1) The electrolyte of claim 1, wherein the ketone is at least one selected from the group consisting of polymethylvinyl ketone and cyclohexanone. ### Claim 7 (depends on 1) The electrolyte of claim 1, wherein the lithium salt is at least one selected from the group consisting of LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiCF3SO3, LiC4F9SO3, LiAlO4, LiAlCl4, LiN(CpF2p+1SO2)(CqF2q+1SO2) (where p and q are natural numbers), LiCl and Lil. ### Claim 8 (depends on 1) A lithium ion secondary battery, comprising: a cathode including a cathode active material that can reversibly intercalate and deintercalate lithium; an anode including an anode active material that can reversibly intercalate and deintercalate lithium; and the electrolyte of claim 1. ### Claim 9 (depends on 2) A lithium ion secondary battery, comprising: a cathode including a cathode active material that can reversibly intercalate and deintercalate lithium; an anode including an anode active material that can reversibly intercalate and deintercalate lithium; and the electrolyte of claim 2. ### Claim 10 (depends on 3) A lithium ion secondary battery, comprising: a cathode including a cathode active material that can reversibly intercalate and deintercalate lithium; an anode including an anode active material that can reversibly intercalate and deintercalate lithium; and the electrolyte of claim 3. ### Claim 11 (depends on 4) A lithium ion secondary battery, comprising: a cathode including a cathode active material that can reversibly intercalate and deintercalate lithium; an anode including an anode active material that can reversibly intercalate and deintercalate lithium; and the electrolyte of claim 4. ### Claim 12 (depends on 5) A lithium ion secondary battery, comprising: a cathode including a cathode active material that can reversibly intercalate and deintercalate lithium; an anode including an anode active material that can reversibly intercalate and deintercalate lithium; and the electrolyte of claim 5. ### Claim 13 (depends on 6) A lithium ion secondary battery, comprising: a cathode including a cathode active material that can reversibly intercalate and deintercalate lithium; an anode including an anode active material that can reversibly intercalate and deintercalate lithium; and the electrolyte of claim 6. ### Claim 14 (depends on 7) A lithium ion secondary battery, comprising: a cathode including a cathode active material that can reversibly intercalate and deintercalate lithium; an anode including an anode active material that can reversibly intercalate and deintercalate lithium; and the electrolyte of claim 7.