LITHIUM ION SECONDARY BATTERY, NEGATIVE ELECTRODE FOR LITHIUM ION SECONDARY BATTERY, BATTERY PACK, ELECTRIC MOTOR VEHICLE, ELECTRIC POWER STORAGE SYSTEM, ELECTRIC MOTOR-DRIVEN TOOL AND ELECTRONIC DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery by which superior battery characteristics can be achieved.SOLUTION: A lithium ion secondary battery comprises: a positive electrode; a negative electrode including an active material; and an electrolytic solution. The active material includes, as constituent elements, Si, O and at least one element M1 of Li, C, Mg, Al, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Ge, Zr, Mo, Ag, Sn, Ba, W, Ta, Na and K. The atomic ratio x(O/Si) of O to Si is 0.5x1.8.SELECTED DRAWING: Figure 4