Lithium ion battery silicon substrate composite negative electrode materials and preparation method thereof

Abstract

The invention provides lithium ion battery silicon substrate composite negative electrode materials and a preparation method of the lithium ion battery silicon substrate composite negative electrode materials, and belongs to the technical field of lithium ion batteries. The prepared lithium ion battery silicon substrate composite negative electrode materials comprise, 23-56 wt% of silicon, 12.1-75.4 wt% of magnesium oxide and 2-12 wt% of graphene. A magnesiothermic reduction method is adopted, and magnesium powder serves as a reducing agent for reducing oxide of silicon (SiOx, and x is larger than 0.5 and smaller than 2) to prepare silicon / magnesium oxide composite materials. Then, the magnesium oxide attached on a reaction product on the surface of the silicon serves as a catalyst. A carbon source is adopted to carry out catalytic chemical vapor deposition so as to generate the graphene. The silicon / magnesium / graphene composite negative electrode materials are prepared. According to a prepared silicon substrate lithium ion battery, after magnesiothermic reduction is carried out on the oxide of the silicon, the magnesium oxide is generated on the interior of the oxide of the silicon, a volume effect of the silicon is relieved, the magnesium oxide generated on the interior and the exterior of the oxide of the silicon has the function of the catalyst, the graphene is catalyzed and generated, the volume effect of the silicon can be further relieved, and electrical conductivity of the materials is remarkably strengthened.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries and provides a preparation method for silicon-based composite negative electrode materials of lithium ion batteries. Background technique [0002] With the rapid development of electronics and information industries, mobile communications, digital cameras and portable computers have been widely used, which has led to the rapid development of lithium-ion batteries, the devices that provide energy for the above-mentioned devices. Compared with traditional nickel-metal hydride batteries and nickel-cadmium batteries, lithium-ion batteries have the advantages of high energy density, high working voltage, small self-discharge, fast charging and discharging, and good safety performance. They are the fastest growing and brightest market prospects. A secondary battery. [0003] At present, the negative electrodes of commercialized lithium-ion batteries mainly use carbonaceous mat...

AI Technical Summary

Problems solved by technology

However, the negative electrode composed of pure silicon powder is accompanied by a very large volume change during the process of lithium intercalation and deintercalation, which affects the cycle stability of the electrode.