LITHIUM SECONDARY BATTERIES AND NONAQUEOUS ELECTROLYTE FOR USE IN THE SAME

The present invention relates to a lithium secondary battery at least comprising: an electrode group comprising a positive electrode, a negative electrode, and a separator interposed between the electrodes; and a nonaqueous electrolyte comprising a nonaqueous solvent and a lithium salt contained therein, the electrode group and the nonaqueous electrolyte being held in a battery case, and the positive electrode and the negative electrode each comprising a current collector and, formed thereon, an active-material layer containing an active material capable of occluding/releasing a lithium ion,wherein the nonaqueous electrolyte is a nonaqueous electrolyte which contains difluorophosphoric acid salt in an amount of 10 ppm or more of the whole nonaqueous electrolyte, wherein the difluorophosphoric acid salt is lithium difluorophosphate, and the positive electrode is:positive electrode [1]: a positive electrode containing a positive-electrode active material containing manganese.