Battery negative electrode material, method for manufacturing same, negative electrode for secondary battery, and secondary battery

A method for manufacturing a battery negative electrode material, the battery negative electrode material being a composite substance comprising silicon material areas of a silicon material, and a carbon material area of a carbon material, formed in a surrounding area of the silicon material areas, separated by cavities at least at a portion;

• the method comprising steps (a) to (c):
• step (a):
• mixing an organic material composition and a coated silicon material that is a silicon precursor coated with silicon oxide and obtaining a composite substance of the organic material composition and the coated silicon material;
• step (b):
• removing the silicon oxide from a composite substance resulting from the step (a);
• and
• step (c):
• carbonizing an organic material constituting the organic material composition by subjecting a composite substance resulting from the step (b) to a main firing at a temperature of 1,000° C. to 1,500° C. in a non-oxidizing gas atmosphere;
• wherein an (002) average interlayer spacing d002 of the carbon material area determined by powder X-ray diffraction using CuKα rays is from 0.365 nm to 0.390 nm, and
• wherein a maximum particle size of the coated silicon material is 1,000 nm or less.