Method for utilizing waste silicon powder and carbon to compound and prepare lithium ion cathode material

Abstract

The invention relates to the field of lithium ion batteries and the micro-nanotechnology field and especially relates to a method for utilizing waste silicon powder and carbon to compound and preparea lithium ion cathode material. The method for utilizing the waste silicon powder and carbon to compound and prepare the lithium ion cathode material comprises the following steps: 1) preparing a silicon powder with a porous surface structure, and 2) preparing a carbon-coated porous silicon compound material. According to the invention, a waste silicon powder of diamond wire cutting generated by aphotovoltaic factory is used as a silicon raw material and a metal catalysis etching method is adopted for preparing the silicon powder with the porous structure; the surface of the silicon powder has ducts of a nano-structure; carbon is wrapped on the surface and the carbon layer can be penetrated into the gaps on the silicon powder surface, so that the combined structure is deeper; the synergistic effect of the carbon silicon compound structure is capable of limiting the volume expansion of the silicon, so that the lithium electric property can be promoted.

Description

Technical field [0001] The invention relates to the field of lithium-ion batteries and micro-nano technology, in particular to a method for preparing lithium-ion negative electrode materials by using waste silicon powder and carbon composite. Background technique [0002] Diamond wire cutting of silicon ingots will be the latest development trend. The silicon powder formed during the cutting process can reach 40% of the total mass, and the reuse of silicon powder has become a hot spot in today's research. Lithium-ion batteries have become a research hotspot in the field of new energy due to their advantages of high working voltage, high energy density, and low environmental pollution. The current negative electrode materials of commercial lithium-ion batteries are generally carbon materials with low volume effect, but their theoretical specific capacity should be 372mAh / g, which limits their application as a high-energy density power source. The theoretical specific capacity of ...

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a method for preparing lithium-ion negative electrode materials by using waste silicon powder and carbon composite. The preparation of lithium-ion negative electrode materials by this method can greatly improve the regeneration value of waste silicon powder, and can also solve the problem of carbon negative electrodes in lithium-ion batteries. Low specific capacity of material theory and volume effect of silicon as negative electrode material