NEGATIVE ELECTRODE MATERIAL FOR USE IN NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY, METHOD OF PRODUCING THE SAME, AND LITHIUM-ION SECONDARY BATTERY

摘要

A method of producing a negative electrode material for use in a non-aqueous electrolyte secondary battery, including: making base powder containing silicon; measuring a volume average particle diameter of this powder by particle size distribution with laser diffractometry; randomly sampling 5000 particles or more from the powder and measuring their roundness; selecting the powder if the volume average particle diameter ranges from 0.5 to 20 μm, the roundness of the sampled particles is 0.93 or more on average, and a ratio of the number of particles having a roundness of 0.85 or less is 5% or less; and coating the selected powder with carbon. A negative electrode material useful for a non-aqueous electrolyte secondary battery that has excellent cycle performance and makes the best use of advantages of a silicon-contained material, a method of producing this negative electrode material, and a lithium-ion secondary battery.