NEGATIVE ELECTRODE MATERIAL, NONAQUEOUS ELECTROLYTE SECONDARY BATTERY, AND METHOD FOR MANUFACTURING NEGATIVE ELECTRODE MATERIAL

摘要

PROBLEM TO BE SOLVED: To provide a negative electrode material which can improve the cycle properties of a nonaqueous electrolyte secondary battery, a method for manufacturing the negative electrode material, and a nonaqueous electrolyte secondary battery using the negative electrode material.SOLUTION: A coating layer 20 comprising a silicon material and carbon fibers is laminated on the outside of a silicon core 10 comprising a negative electrode material in a particulate form. The coating layer 20 is so composed that a first region 21 thereof which is located at the boundary with the silicon core 10 contains the carbon fibers and a second region 22 which is located on the outside of the first region 21 contains the silicon material and the carbon fibers. The content of the carbon fibers is larger than that of the silicon material in the first region 21, and the content of the silicon material in the second region 22 is 50 mass% or more based on the total mass (100 mass%) of the second region.