Hollow porous micron-scale silicon sphere, silicon-based negative electrode material and preparation method of lithium ion battery

Abstract

The invention provides a preparation method of hollow porous micron order silicon spheres, a silicon-based cathode material and a lithium ion battery. The preparation method comprises the following steps: reducing hollow glass beads by using active metals; then removing metal oxides by acid to obtain the hollow porous micron order silicon spheres; and preparing the silicon-based negative electrode and the lithium ion battery based on the hollow porous micron order silicon spheres. As the prepared hollow porous micron order silicon spheres have a lot of holes and pores in the porous walls and in the spheres, the specific discharge capacity of the battery is greatly improved, and volume explanation and shrinkage in a lithium insertion / extraction process are fully inhibited by means of the holes and pores in the porous walls and in the spheres. Moreover, as the spherical structures are very stable, pulverizing and falling phenomena of the electric active substances can be eliminated, so that the service life of the silicon-based cathode material is prolonged. The synthetic method of the hollow porous micron order silicon spheres is simple and the technical problem of capacity and service life of the high-capacity lithium ion battery is effectively solved.

Description

technical field [0001] The present invention relates to the preparation technology of lithium-ion battery negative electrode materials, in particular to a method for preparing hollow porous micron-sized silicon spheres, a method for preparing silicon-based negative electrode materials based on the hollow porous micron-sized silicon spheres, and a silicon-based negative electrode based on the described silicon-based negative electrode materials. Materials for the preparation of lithium-ion batteries. Background technique [0002] At present, the lithium-ion batteries used in production mainly use graphitized carbon as the negative electrode material, but the lithium storage capacity of the material is not high. As far as graphite-based negative electrode materials are concerned, their large layered structure voids not only provide a place for lithium storage, but also determine the characteristics of the material's low theoretical specific capacity (about 372mAh / g). Therefor...

AI Technical Summary

Problems solved by technology

However, the silicon negative electrode is accompanied by serious volume expansion and contraction during the process of intercalating and removing lithium, which leads to the powdering and falling off of the electroactive material on the electrode, and finally leads to capacity fading.

The development of silicon-containing composite materials has gradually become the focus of people's research. The research idea is generally to form alloys of silicon and other inactive metals (such as Fe, Al, Cu, etc.). Carbon composite materials are used to prepare lithium-ion battery negative electrodes, or silicon materials are evenly dispersed into other active or inactive materials to form composite materials, such as Si-C, Si-TiN and other lithium-ion battery negative electrodes widely used in the prior art. Capacitive silicon-carbon composite materials. Although these existing silicon-based composite materials can improve their cycle stability and capacity fading as lithium-ion battery negative electrodes to a certain extent, their mechanisms are simple physical composite or high-temperature carbon coating. , can not fundamentally suppress the volume effect in the process of charge and discharge, after many cycles, the capacity will begin to decay rapidly

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