A method for preparing porous silicon nano fiber / carbon composite material

The present invention relates to a porous silicon nano fiber / carbon composite material preparation method, belonging to the technical field of lithium ion batteries. The first acid leaching chrysotile asbestos, washed with water, filtered and dried to obtain the removal of alkali metal oxide impurities of silica nanofibers; was added to the silica nanofibers mixed uniformly reducing metal reduction reaction to give the reduction product reduction products pickled, washed with water, and dried to obtain a porous silicon nanofibers prepared; the resulting porous silicon precursor and carbon nanofibers uniformly mixed to give mixed material, the mixed material was then dissolved in a solvent, under conditions and ultrasound dispersing the mixture obtained, after dispersing the mixture in an inert atmosphere for carbonizing the preparation or hydrothermal carbonization to obtain a porous silicon nano fiber / carbon composite material pyrolysis. The method as natural mineral raw material, low cost and simple; the porous silicon nano fiber / carbon composite material having a large capacity density, high initial coulombic efficiency, stable cycle performance characteristics.