NEGATIVE ELECTRODE MATERIAL FOR NONAQUEOUS SECONDARY BATTERY, NEGATIVE ELECTRODE FOR NONAQUEOUS SECONDARY BATTERY, AND NONAQUEOUS SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a negative electrode material for a nonaqueous secondary battery that has both high capacity and high cycle characteristics, a negative electrode for the nonaqueous secondary battery, and the nonaqueous secondary battery.SOLUTION: There is provided a negative electrode material for a nonaqueous secondary battery that includes carbonaceous particles (A) and silicon oxide particles (B), the carbonaceous particles (A) being approximate ellipsoids having an ellipticity (f) of 0.38-0.68 represented by expression (1) of f=1-b/a(1) calculated from a major diameter (a) and a minor diameter (b) found in the following measuring method, where approximate ellipsoid sections are obtained through image analyzing software from respective sectional ellipses of 100 carbonaceous particles in an image of an electrode section photographed by a scanning type electron microscope after an electrode of 6-20 mg/cmin weight of an active material layer obtained by mixing only carbonaceous particles (A) and a binding resin is cut by a cross section polisher while pressed to an active material density of 1.2 to 1.8 g/cmor not pressed, average values of respective major diameters and minor diameters which are thus measured being a major diameter (a) and a minor diameter (b).