NEGATIVE ELECTRODE ACTIVE MATERIAL FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERIES AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY USING SAME

摘要

The present invention improves initial charge/discharge efficiency and cycle characteristics of a nonaqueous electrolyte secondary battery which uses SiOx as a negative electrode active material. Provided is a negative electrode active material for nonaqueous electrolyte secondary batteries, which is composed of particles formed of SiOx (wherein 0.8 ≤ x ≤ 1.2), each of said particles having cracks inside. It is preferable that SiOx contains a lithium silicate phase and an Si-M compound or an oxide of M (M is at least one element selected from among Al, Ti, Fe and Ni). It is also preferable that the cracks are formed radially from an inner part of each particle.