Electrolyte solution and battery containing the same

摘要

Provided are an electrolyte solution and a battery which are capable of improving cycle characteristics. An anode includes a simple substance, an alloy or a compound of a metal element or a metalloid element capable of forming an alloy with lithium as an anode active material. A separator is impregnated with an electrolyte solution formed through dissolving an electrolyte salt in a solvent. The electrolyte salt includes a first electrolyte salt including LiB(C 2 O 4 ) 2 and a second electrolyte salt including at least one kind selected from the group consisting of LiPF 6 , LiBF 4 , LiN(CF 3 SO 2 ) 2 , LiN(C 2 F 5 SO 2 ) 2 , LiClO 4 , LiAsF 6 and LiC(CF 3 SO 2 ) 3 . In the solvent, 4-fluoroethylene carbonate is included. A coating is formed on the anode by the first electrolyte salt, and high ionic conductivity can be obtained by the second electrolyte salt. Further an oxidation-decomposition reaction of the electrolyte solution which occurs in a cathode can be prevented by 4-fluoroethylene carbonate.