▎ 摘　　要

NOVELTY - Composite silicon-based material comprises a silicon base body (1) and a conductive carbon layer (2). The conductive carbon layer is combined on the surface of the silicon base body and a buffer space (3) is formed between the silicon base body and the conductive carbon layer. USE - The cathode is useful in secondary battery (claimed). ADVANTAGE - The material utilizes the buffer space provided between the conductive carbon layer and the surface of the silicon base body which can alleviate the deformation effect of the composite silicon-based material in the lithium storage process; improves the cycle performance; has low capacity attenuation and utilizes conductive carbon layer, which improves the conductivity and rate performance of the composite silicon-based material. The method ensures that the performance of the composite silicon-based material is stable; has high efficiency and saves production cost. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: preparing composite silicon-based material comprising providing silicon base body, forming a mold layer on the surface of the silicon base body, forming a conductive carbon layer on the outer surface of the mold layer, removing the mold layer, making the conductive carbon layer bonded on the surface of the silicon base body and forming a buffer space between the conductive carbon layer and the silicon base body to obtain a composite silicon-based material; and a cathode comprising composite silicon-based material. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the composite silicon-based material in secondary battery. 1Silicon base body 2Conductive carbon layer 3Buffer space