Patent ID: 7781099

Claim:
A non-aqueous electrolyte secondary battery comprising: a negative electrode with a composite layer containing a negative active material; a positive electrode; and a non-aqueous electrolyte; characterized in that said negative active material is an alloy containing 5 to 25 mass % of nickel and 75 to 95 mass % of tin, said alloy contains Sn 4 Ni 3 phase and Sn phase, and the content ratio of said Sn 4 Ni 3 phase and said Sn phase in said alloy is 0.2≦Z≦3 when m 1 is the mass of said Sn 4 Ni 3 phase, m 2 is the mass of said Sn phase, and Z=m 1 / m 2 .