NEGATIVE ELECTRODE ACTIVE MATERIAL FOR ELECTRIC DEVICE AND ELECTRIC DEVICE USING SAME

An object of the present invention is to provide a negative electrode active material that is for an electric device such as a lithium ion secondary battery and that has high cycle durability. The negative electrode active material for an electric device of the present invention contains an alloy represented by the following chemical formula (1): [Chem. 1] Si x Sn y M z A a (1) (in the chemical formula (1), M is at least one metal selected from the group consisting of Ti, Zn, C, and combinations thereof, A is unavoidable impurities, x, y, z, and a represent % by mass values, and in that case, 0 < x < 100, 0 < y < 100, 0 < z < 100, 0 ¤ a < 0.5, and x + y + z + a = 100), in which the half width of the diffraction peak of the (111) surface of Si in the range of 2¸ = 24 to 33° by X ray diffraction measurement of the alloy using the CuK± ray is 0.7° or more.