Patent ID: 7709157

Claim:
A non-aqueous electrolyte secondary battery comprising: (a) a chargeable and dischargeable positive electrode, said positive electrode necessitates to be charged at a potential of 3.7 V or higher relative to a potential of metal lithium and comprises a current collector comprising aluminum; (b) a negative electrode to absorb and desorb lithium; (c) a separator to prevent direct electron transfer between said positive electrode and said negative electrode; and (d) a non-aqueous electrolyte; said non-aqueous electrolyte comprising a non-aqueous solvent and a solute, said non-aqueous solvent consisting of a lactone comprising γ-butyrolactone, and said solute comprising lithium bis(fluorosulfonyl)imide represented by the formula (1): (F—O 2 S—N—SO 2 —F)Li, and a second lithium salt, wherein: said second lithium salt containing a fluorine atom, and said second lithium salt is at least one selected from the group consisting of LiPF m (C k F 2k+1 ) 6−m (0≦m≦6, 1≦k≦2), and LiBF n (C j F 2j+1 ) 4−n (0≦n≦4, 1≦j≦2).