Abstract: A negative electrode material for a nonaqueous electrolyte rechargeable battery that can stably and efficiently realize a high-performance nonaqueous electrolyte rechargeable battery in which a high discharge capacity, high charge/discharge efficiency at an initial stage and during charge/discharge cycles, and excellent charge/discharge cycle properties are provided as well as electrode expansion in volume after charge/discharge cycles is suppressed. The negative electrode material for a nonaqueous electrolyte rechargeable battery in the form of particles having, at least on the surface thereof, a compound of the phase in which an element Z is present in Si in a non-equilibrium state.

Abstract: A negative electrode material for a nonaqueous electrolyte rechargeable battery that can stably and efficiently realize a high-performance nonaqueous electrolyte rechargeable battery in which a high discharge capacity, high charge/discharge efficiency at an initial stage and during charge/discharge cycles, and excellent charge/discharge cycle properties are provided as well as electrode expansion in volume after charge/discharge cycles is suppressed. The negative electrode material for a nonaqueous electrolyte rechargeable battery in the form of particles having, at least on the surface thereof, a compound of the phase in which an element Z is present in Si in a non-equilibrium state.

Abstract: A negative electrode yields a high-performance nonaqueous electrolyte secondary battery which has a high discharging capacity, high charging/discharging efficiency in the initial stage and during cyclic operation, and excellent properties in cyclic operation, and the electrode of which less expands after cyclic operation. The negative electrode includes an active material thin film which mainly contains a compound represented by a general formula SiZxMy, wherein Z, M, “x” and “y” satisfy the following conditions, of a phase including an element Z lying in a nonequilibrium state in silicon. The element Z is at least one element selected from the group consisting of boron, carbon, and nitrogen. The element M is other than silicon and the element Z and is at least one element selected from the elements of Groups 2, 4, 8, 9, 10, 11, 13, 14, 15, and 16 of the Periodic Table of Elements. The number “x” is such a value that a Z-concentration ratio Q(Z) falls within the range of 0.10 to 0.95.