The invention discloses a method for preparing a
silicon-carbon composite negative
electrode material through an electrostatic self-
assembly technology, and belongs to the technical field of
lithium ion battery negative
electrode materials. According to the invention,
lignin is used as a
biomass carbon source and lauryl
sodium sulfate (SDS) and poly (
diallyldimethylammonium chloride) (PDDA) are used as activators through a simple electrostatic self-
assembly technology; a proper amount of
nano silicon and PDDA are subjected to in-situ adsorption, and
lignin and SDS are subjected to in-situ adsorption; a self-
assembly process is carried out through the positive and
negative charge attraction effect among colloidal particles, so that effective compounding of the
nano silicon particles and the
biomass carbon is realized; and performing
vacuum drying, and performing one-stage
sintering in a tubular furnace to obtain the
silicon-carbon composite negative
electrode material. Based on the problems of non-uniform particle size, easy agglomeration and great abrasion of a
silicon-carbon
composite material in a traditional mechanical synthesis technology, the invention improves the compounding efficiency of the silicon-carbon material and improves the problems of
volume expansion of a silicon negative electrode, slow migration rate of
lithium ions, poor cycle performance and the like.