Method for preparing porous graphene silicon negative electrode material

Abstract

The invention relates to a method for preparing a porous graphene silicon negative electrode material. For the problem that the volume expansion of a current silicon negative electrode material seriously causes structural collapse to cause rapid collapse to cause the quick attenuation of energy, a metal oxide-graphene composite material is prepared by using a graphite intercalation method, a liquid phase stripping method and an in-situ growth method, the surface of a silicon material is coated with the metal oxide-graphene composite material, then the metal oxide is etched away with an acid solution, and the porous graphene silicon negative electrode material is obtained by the principle of carbothermal reaction. The excellent conductivity and porous structure of high-quality graphene facilitate the rapid transmission of electrons and lithium ions, a variety of pore graphene structures can be obtained by controlling heat treatment time and temperature, the flexible adjustment can be carried out according to conditions needed by an actual negative electrode material, the etched metal oxide leaves a buffer space, and a series of negative effects caused by the volume expansion of thesilicon material are alleviated.

Description

technical field [0001] The invention belongs to the field of lithium ion battery negative electrode materials, and in particular relates to a preparation method of a porous graphene silicon negative electrode material and a lithium ion battery using the negative electrode material. Background technique [0002] As a negative electrode material for lithium batteries, silicon materials have extremely high theoretical specific capacity (>3000mA h g-1), and are expected to become a new generation of negative electrode materials that can replace graphite materials with low lithium storage capacity. However, the volume expansion of silicon during charge and discharge is serious (about 4 times), which causes the particles to squeeze each other and cause the structure to collapse, and the silicon material is easy to fall off from the current collector, thus causing rapid energy decay of the battery. Application of negative electrode materials. [0003] Graphene, a two-dimensiona...

AI Technical Summary

Problems solved by technology

The main method is to load metal oxide on the surface of redox graphene, and then reduce and etch it. This method causes irreparable damage to the structure of graphene, and uses a large amount of highly toxic substances such as acid and alkali in the preparation process. , low yield, difficult to scale production

In addition, plasma sputtering, microwave method, ultrasonic treatment, gas etching and other methods are also used, but most of these technologies are expensive, poorly controllable and difficult to apply on a large scale