▎ 摘　　要

NOVELTY - A negative electrode active material has a core-shell structure. The core portion comprises silicon nanowire and an inactivated material. The silicon nanowire forms a three-dimensional network structure, and the inactivated material is filled in the void positions of the three-dimensional network structure. The shell portion comprises a shell (S1) and a shell (S2). The shell (S1) covers the surface of the core, and comprises conductive carbon. The shell (S2) covers the surface of the shell (S1), and comprises a fast ion conductor. USE - Negative electrode active material is used as negative electrode of lithium battery. ADVANTAGE - The negative electrode active material is prepared using silicon nanowire, and inactivated material which reacts with hydrogen fluoride and other components under the condition of shell rupture to protect the negative electrode active material, and reduce specific surface area of the material and surface activity of silicon nanowire. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of the negative electrode active material.