Negative electrode active material, negative electrode, lithium ion secondary battery, method of using lithium ion secondary battery, method of producing negative electrode active material, and method of producing lithium ion secondary battery

Abstract

A negative electrode active material including a negative electrode active material particle; the negative electrode active material particle including a silicon compound shown by SiOx (0.5≤x≤1.6), wherein at least part of the Si4+ contained in the negative electrode active material particle is to be changed to at least one state selected from valence states of Siy+ (y is any of 0, 1, 2, and 3) in occlusion of Li in the negative electrode active material. This provides a negative electrode active material that is capable of increasing battery capacity and improving cycle performance when it is used as a negative electrode active material for a secondary battery.

Dependencies are inferred from the claim text.