COMPOSITE NEGATIVE ELECTRODE ACTIVE MATERIAL BODY, NEGATIVE ELECTRODE FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERIES, AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a composite negative electrode active material body for nonaqueous electrolyte secondary batteries which enables the improvement of a nonaqueous electrolyte secondary battery in cycle characteristic while using a silicon-based negative electrode active material, a negative electrode for nonaqueous electrolyte secondary batteries which is arranged by use of such a composite negative electrode active material body, and a nonaqueous electrolyte secondary battery using such a negative electrode.SOLUTION: A composite negative electrode active material body comprises: silicon particles made of a silicon-based negative electrode active material; a C-coated layer provided on each silicon particle; and a transition metal layer provided between each silicon particle and the C-coated layer. The transition metal layer includes at least one metal selected from tungsten (W), titanium (Ti) and tantalum (Ta). The amount of the carbon (C) is within a range of 0.25-10.0 mass% to 100 mass% of the silicon particles.