Silicon-based anode material for secondary battery and preparation method thereof, secondary battery

Abstract

A silicon-based anode material for secondary batteries, a preparation method thereof and a secondary battery are provided. The silicon-based anode material includes: an inner core including an Si particle and silicon oxide SiO, where 0<x1<2, a first shell layer including a compound of the general formula MSiO(0<y≤4, 0<z≤5, and z≥x1) and a C particle, wherein the first shell layer covers the inner core, and the contents of M and C in the first shell layer gradually increase from a side thereof close to the inner core to another side thereof far away from the inner core; and a second shell layer including a carbon film layer or a composite film layer formed by a carbon film layer and a conductive additive, the second shell layer covers the first shell layer. The first charge-discharge cycle capability of the silicon-based anode material is improved, and the manufacturing cost is reduced.