| 摘要 |
PURPOSE: Provided are a negative electrode active material for a lithium secondary battery which inhibits the expansion and contraction of powder itself and prevents the decomposition of an electrolyte solution at the surface of powder, its preparation method, and a lithium secondary battery containing the active material. CONSTITUTION: The negative electrode active material comprises a multi-phase alloy powder(1) comprising a Si phase(2), a SiM phase(3) and at least one(4) of an X phase and a SiX phase, and the amount of the Si phase at the particle surface of the multi-phase alloy powder is smaller than that of the Si phase at the inside of particle, wherein M is at least one selected from the group consisting of Ni, Co, As, B, Cr, Cu, Fe, Mg, Mn and Y; X is at least one selected from the group consisting of Ag, Cu and Au; and both M and X are not Cu simultaneously. Preferably a micropore(5) is formed on the particle surface of the multi-phase alloy powder. |
