| abstract |
PROBLEM TO BE SOLVED: To provide a secondary lithium ion battery which can be charged to a high voltage (more than 4.35V with a full battery) and has good stability and low impedance increase during high temperature storage. Is. An electrolyte containing a cathode containing a dope LiCoO 2 active material, an anode containing graphite, a carbonate solvent, a lithium salt, and both succinonitrile (SN) and lithium bis (oxalat) borate (LiBOB) additives. The difference in SOC between 4.42V and 4.35V between the discharge at 45 ° C. at C / 10 rate from the 100% charged (SOC) state at 4.5V to 0 SOC at 3V The active material has an working voltage of 4.35 V or greater, at least 7% or more and less than 14%, and the active material is doped with at least 0.5 mol% of any one or more of Mn, Mg and Ti. Lithium secondary battery. [Selection diagram] Fig. 2 |