Porous silicon carbon negative electrode material and preparation method thereof

Abstract

The invention relates to the technical field of electrode materials, in particular to a porous silicon carbon negative electrode material and a preparation method thereof.The preparation method comprises the following steps that a silicon material is dispersed in a solvent, graphene oxide dispersion liquid and a transition metal ion solution are added, polyacrylamide and a sodium hypophosphite solution are dropwise added, and a silicon material precipitate is generated, wherein the surface of the silicon material contains transition metal M and graphene oxide; a silicon material precipitate is taken; under the protective atmosphere, high-temperature heating is carried out, graphene oxide is reduced into graphene, a prefabricated layer is formed on the surface of the silicon material, cooling is carried out, and the silicon material coated with the prefabricated layer is obtained; pickling of the silicon material coated with the prefabricated layer is carried out, and the transition metal M in the prefabricated layer is removed to form a graphite silicon material with a porous structure; the graphite silicon material with a porous structure is added into a carbon precursor, and carbon coating treatment is carried out to form a porous silicon carbon negative electrode material crude product; and carbonizing of the porous silicon carbon negative electrode material crude product is carried out to obtain the porous silicon carbon negative electrode material.

Description

technical field [0001] The invention relates to the technical field of electrode materials, in particular to a porous silicon-carbon negative electrode material and a preparation method thereof. Background technique [0002] Due to the important advantages of high voltage and high capacity, long cycle life and good safety performance, lithium-ion batteries have broad applications in portable electronic devices, electric vehicles, energy storage, space technology, biomedical engineering, and defense industries. It has become a research and new energy industry development hotspot that has attracted wide attention in the past ten years and for a long time to come. [0003] Carbon materials, such as natural graphite, graphitized mesocarbon microspheres, etc., are widely used in lithium-ion battery anode materials. Among non-carbon anode materials, silicon has a very high theoretical specific capacity, a low lithium storage reaction voltage platform, and silicon is widely distri...

AI Technical Summary

Problems solved by technology

However, the electronic conductivity and ionic conductivity of silicon are low, resulting in poor kinetic performance of its electrochemical reactions; the cycle stability of ordinary pure silicon is poor

Moreover, the phase change and volume expansion of silicon in the lithiation process will generate greater stress, resulting in electrode fracture and pulverization, increased resistance, and a sudden drop in cycle performance.

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