▎ 摘　　要

NOVELTY - Negative electrode active material has a core-shell structure. The core in the core shell structure is silicon-based material. The shell in the core-shell structure is titanium silicide. The shell covers at least a portion of the surface of the inner core and coating layer, the coating layer covers at least a portion of the surface of the core-shell structure, the coating layer is a conductive material, the conductive material is directly grown on the surface of the core shell structure. USE - Negative electrode active material used in a lithium ion battery (claimed). ADVANTAGE - The negative electrode active material has titanium silicide which improve the mechanical strength and hardness of the negative electrode material, suppresses the volume strain/stress of silicon, maintains better structural stability of the silicon negative electrode, and improve the cycle performance of the battery and conductive material can increase the conductivity and improve the battery rate performance; and the conductive material grows directly on the surface of the core-shell structure, which can prevent the conductive material from falling off the surface of the silicon material during the subsequent homogenization process, and can also better inhibit the material from being deposited on the surface of the silicon material. It also has better effect of inhibiting the expansion of the material in the circulation process, it not only increases the conductivity of the material, but also improves the structure stability. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: 1. a method for preparing negative electrode active material, which involves mixing the silicon-based material with titanium source, ball milling to obtain mixed powder, sintering the mixed powder in the non-oxidizing atmosphere to obtain the core-shell structure, adding the core-shell structure and the conductive material into the polar solvent to mix uniformly, using solvent thermal method to form the coating layer; and 2. a lithium ion battery, which comprises negative electrode active material.