NEGATIVE ELECTRODE MATERIAL FOR SECONDARY BATTERY

A negative electrode material for a secondary battery includes a matrix containing silicon oxide, a composite oxide of one or more doping elements selected from the group consisting of an alkali metal, an alkaline earth metal, and a post-transition metal, and silicon, or a mixture thereof; and silicon nanoparticles dispersed and embedded in the matrix; wherein a hardness and a Young's modulus measured by a nanoindentation test are 4.0 GPa or more and 40 GPa or more, respectively, and in an X-ray diffraction pattern using a CuKα ray, a ratio (A/A) of an area (A) of a first peak present in a region where a diffraction angle θ is 10° to 27.4° to an area (A) of a second peak present in a region where the diffraction angle θ is 28±0.5° is 0.8 to 6.