NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

Provided is a nonaqueous electrolyte secondary battery which is prevented in the deterioration of storage characteristics due to the elution of Si from a negative electrode in case of discharge or the precipitation of eluted Si. The nonaqueous electrolyte secondary battery comprises a positive electrode which can absorb and desorb Li electrochemically; a negative electrode which comprises a negative electrode active material containing at least Si; and a nonaqueous electrolyte solution which contains lithium hexafluorophosphate as a main supporting electrolyte and contains 50-200 ppm of an acid. Preferably the negative electrode has a potential of 0.6-1.5 V based on a Li electrode at the discharge cut-off voltage.