NEGATIVE ELECTRODE MATERIAL AND PREPARATION METHOD THEREFOR

摘要

Disclosed are a negative electrode material and a preparation method therefor, where the technical problem to be solved is to improve the safety of lithium-ion batteries and to reduce preparation costs. The negative electrode material of the present invention is a composite material consisting of a substrate and a covering layer covering same, where the substrate is a graphite-type material having a carbon content of over 99.9%, the substrate comprises nanopores or nanogaps, and where the covering layer is a carbon material. The preparation method for the negative electrode material of the present invention comprises the following steps: oxidizing/reducing the graphite-type material, and solid-phase coating or liquid-phase coating a soft carbon prone to graphitization or an organic pyrolytic carbon. Compared with the prior art, the present invention controls surface functional groups of a processing layer and/or of the covering layer on the surface of the negative electrode material, thus allowing the processing layer and the covering layer to be thin and uniform, improving the stability and thermal conductivity thereof in electrolytes, and improving the safety of lithium-ion batteries. The negative electrode material is provided with a great capacity, great efficiency, simplified preparation process, and reduced costs for preparing the negative electrode material.