▎ 摘　　要

NOVELTY - A cathode active material comprises a silicon-carbon composite comprising silicon oxide and graphite with ratio of Dv50 particle size of graphite and Dv50 particle size of silicon oxide of 2-6 (excluding 6). USE - Cathode active material for electrochemical device used in e.g. lithium-ion battery for electronic device (all claimed). ADVANTAGE - The battery using the cathode active material has improved cycle life and cycle stability. DETAILED DESCRIPTION - A cathode active material comprises a silicon-carbon composite comprising silicon oxide (SiOx, where x is 0.5-1.6) and graphite. The ratio of Dv50 particle size of graphite and Dv50 particle size of silicon oxide of 2-6 (excluding 6).