A kind of preparation method of three-dimensional porous graphene microsphere composite material

Abstract

The invention discloses a method for preparing a three-dimensional porous graphene microsphere composite material. The method comprises the steps of 1, mixing graphene or oxidized graphene with water and a binder to prepare a solution, and then conducting electrostatic spraying and wet process collection to obtain graphene or oxidized graphene microspheres; 2, adding the graphene microspheres into a PVA aqueous solution, conducting stirring and dispersion, and adding a cross-linking agent dropwise to form PVA gel; 3, conducting freeze drying on the PVA gel to prepare PVA sponge containing the graphene microspheres; 4, conducting heat treatment to obtain the three-dimensional porous graphene microsphere composite material. The three-dimensional porous graphene microsphere composite material prepared with the method has the advantages that the structure is stable, rich hierarchical pore structures are obtained and bulk density is high. A sodium-ion battery prepared with the graphene microsphere composite material has the advantages of being high in capacity, high in conductivity, excellent in cycle performance and high in packing density.

Description

technical field [0001] The invention belongs to the field of nano-carbon materials and preparation thereof, in particular to a preparation method of a three-dimensional porous graphene microsphere composite material. Background technique [0002] Lithium-ion batteries have excellent properties such as high specific energy, small memory effect, and less environmental pollution. They have become widely used secondary batteries in electronic products such as mobile phones and notebook computers. It also has great application prospects. However, negative electrode materials play a decisive role in improving the performance of lithium-ion batteries. Traditional lithium battery negative electrode materials mainly use carbonaceous materials such as graphite. Graphite materials have good cycle stability, but their capacity is only 372mAh / g compared to the theoretical capacity. Without the further improvement of the performance of lithium-ion batteries, it is difficult to meet peopl...

AI Technical Summary

Problems solved by technology

[0004] At this stage, there are few researches on the development of graphene-modified electrode materials for energy storage devices such as sodium-ion batteries.

In 2013, Wang et al. used graphene oxide and pyrrole as raw materials to synthesize a 2D porous doped carbon / graphene composite material through heat treatment and carbonization. The introduction of heteroatoms improved the electronic conductivity and capacity of the material; in 2014, Yan Yang et al. constructed a porous carbon / graphene nanocomposite material with a sandwich structure by ion thermal method. Although the porous carbon ensures the reversible deintercalation of Na+ and the graphene layer promotes the rapid transport of electrons, it still There are disadvantages such as large specific surface area leading to high initial irreversible capacity