The invention relates to a multi-core core-shell-structure
silicon carbon composite negative pole material and a preparation method thereof. The preparation method comprises the following steps: 1. preparation method of high-dispersivity multi-core
porous spheres; 2. preparation of high-dispersivity
asphalt suspension; and 3. preparation of multi-core core-shell-structure
silicon carbon composite negative pole material: adding the
porous spheres prepared in the step 1 into the high-dispersivity
asphalt suspension prepared in the step 2, carrying out
ultrasonic dispersion, heating and
drying by
distillation while intensely stirring to remove the
solvent, transferring the
powder particles into a protective
atmosphere, and holding at low temperature so that the
asphalt liquid enters the inside of the
porous spheres to enhance the binding strength between the
silicon source and the conducting carbon mesh, carry out secondary
coating on the silicon source, overcome the defects in the
coating in the step 1 and enhance the capacity performance of the silicon; and carrying out high-heat treatment. The invention is simple and easy to implement, and has the
advantage of high practicality. The prepared silicon carbon
composite material has the advantages of high reversible capacity, designable capacity, favorable cycle performance, favorable heavy-current
discharge capacity, high tap density and the like.