Application of graphene/silicon-carbon composite material in lithium ion battery prepared by using microcrystalline graphite as carbon source

Abstract

The invention discloses application of a graphene / silicon-carbon composite material in a lithium ion battery prepared by using microcrystalline graphite as a carbon source. Copper foil deposited withthe graphene / silicon carbon composite material is punched into a pole piece, a lithium piece is used as a counter electrode in an argon-filled glove box, a polypropylene microporous membrane is adopted as a diaphragm, 1 mol L-1 lithium hexafluorophosphate (LiPF6) which is a mixture of dimethyl carbonate (DMC) and ethylene carbonate (EC) at the volume ratio of 1:1 is adopted as an electrolyte, anda battery is assembled. The lithium ion battery prepared by using the copper foil deposited with the graphene / silicon-carbon composite material has the advantages of being high in reversible capacity,designable in capacity, good in cycle performance and high current discharge capability and high in tap density.

Description

technical field [0001] The invention belongs to the technical field of preparation of composite materials, and more specifically relates to the application of a graphene / silicon-carbon composite material prepared by using microcrystalline graphite as a carbon source in lithium-ion batteries. 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 mai...

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