Method for preparing graphene/silicon carbon composite material by taking microcrystalline graphite as carbon source

Abstract

The invention discloses a method for preparing a graphene / silicon carbon composite material by taking microcrystalline graphite as a carbon source. According to the invention, microcrystalline graphite powder is taken as the carbon source, is mixed with graphene oxide dispersion liquid, primary vapour deposition is carried out on copper foil, a transition layer is formed, a stable and firm adhesion point with certain toughness is provided for silicon deposition, and electrode conductivity is increased. The nano dots and nano wires are distributed on a carbon network transition layer, which hasthe growth guiding effect during a secondary vapour deposition process, and a specific shape is generated. The graphene / silicon carbon composite material is composed of several nano particles, has good mechanical strength and toughness, and can effectively reduce the shedding of an active material due to volume expansion of silicon. The material has the characteristics of large reversible capacity, capacity design , good cycle performance and heavy current discharge capability, and high tap density.

Description

technical field [0001] The invention belongs to the technical field of preparation of composite materials, and more specifically relates to a method for preparing graphene / silicon-carbon composite materials using microcrystalline graphite as a carbon source. Background technique [0002] Due to the advantages of large specific energy, high working voltage, good safety, and low environmental pollution, lithium-ion batteries have broad application prospects in various portable electronic devices, electric vehicles, and new energy storage. Generally speaking, as the main body of lithium-ion battery storage, the negative electrode material realizes the intercalation and extraction of lithium ions during the charging and discharging process, which is the key to improving the specific capacity, cycle performance, charge-discharge and other related performance of lithium-ion batteries. At present, the commercial negative electrode materials are mainly traditional carbon materials b...

AI Technical Summary

Problems solved by technology

However, due to the volume expansion of silicon, its structure will be destroyed during the charging and discharging process, the active material will fall off from the current collector, and an irreversible electrolyte film will continue to form, which will eventually lead to low reversible capacity and poor cycle stability of silicon negative electrode materials. and rate performance