Non-aqueous electrolyte comprising a hexafluorophosphate and a difluorophosphate

Provided is a nonaqueous electrolyte for a secondary battery which comprises a nonaqueous solvent containing at least a hexafluorophosphate as an electrolyte lithium salt; a difluorophosphate; and a fluoride salt. Also provided is a nonaqueous-electrolyte secondary battery comprising the above nonaqueous electrolyte together with a negative electrode capable of occluding and releasing lithium ions and a positive electrode.