NEGATIVE ELECTRODE ACTIVE SUBSTANCE FOR NONAQUEOUS ELECTROLYTE SECONDARY CELL, NEGATIVE ELECTRODE FOR NONAQUEOUS ELECTROLYTE SECONDARY CELL, NONAQUEOUS ELECTROLYTE SECONDARY CELL, AND METHOD FOR PRODUCING NEGATIVE ELECTRODE MATERIAL FOR NONAQUEOUS ELECTROLYTE SECONDARY CELL

摘要

The present invention is a negative electrode active substance for a nonaqueous electrolyte secondary cell, the substance having negative electrode active substance particles, the negative electrode active substance particles comprising a silicon compound (SiOx: 0.5 < x < 1.6), wherein the negative electrode active substance particles are at least partially coated by a carbon film formed from a substance containing carbon, the density of the carbon film is 1.2 to 1.9 g/cm3, and the adsorption-desorption isotherm of the negative electrode active substance particles has an IUPAC classification characterized as type II or type III as obtained by adsorption-desorption isotherm measurement with nitrogen gas. Due to this configuration, provided is a negative electrode active substance for a nonaqueous electrolyte secondary cell, and by the negative electrode active substance, cell capacity can be increased and cycle properties and cell initial efficiency can be improved.