▎ 摘　　要

NOVELTY - Composite silicon material comprises multiple base particles and a first conductive material dispersed between the base particles, the base particles includes a silicon material and a coating layer coated on outer surface of the silicon material, the coating layer includes magnesium hydroxide, magnesium oxide, and carbon material, the first conductive material includes graphene and/or conductive carbon tube. USE - The composite silicon material is useful in lithium ion battery (claimed). ADVANTAGE - The composite silicon material further improves the cycle performance and safety of the lithium ion battery on the basis of improving the energy density of the lithium ion battery and improves the safety of the lithium ion battery.