Si-C-N composite negative pole material and preparation method thereof

The invention discloses a Si-C-N composite negative pole material and a preparation method thereof and belongs to the field of lithium ion battery negative pole materials. The preparation method comprises the following steps of heating a mixture of a Si source and an N source to a temperature of 600-1000 DEG C at a heating rate of 0.5-10 DEG C/min in an Ar atmosphere, carrying out sintering at a temperature of 600-1000 DEG C for 3-15h, carrying out cooling to a room temperature to obtain an N-doped Si-based material, mixing the N-doped Si-based material and graphite to obtain a uniform mixture, heating the mixture of the N-doped Si-based material and graphite to a temperature of 500-900 DEG C at a heating rate of 0.5-10 DEG C/min in an N atmosphere, carrying out sintering at a temperature of 500-900 DEG C for 1-10h, and carrying out cooling to a room temperature to obtain the Si-C-N composite negative pole material. Through use of N in the Si material, Si material bandwidth is reduced and conductivity is improved. Through coating of the N-doped Si-based material with graphite, volume effects of the Si material is effectively buffered. The Si-C-N composite negative pole material has excellent multiplying power performances and cycle stability.