One-step in situ preparation of liquid-exfoliated pristine graphene/Si composites: towards practical anodes for commercial lithium-ion batteries

Abstract

The cost-effective, scalable, and reproducible production of a graphene/Si (Gra/Si) composite still holds the key to their commercialization as anodes for lithium-ion batteries (LIBs). Herein, we report the one-step in situ preparation of liquid-exfoliated Gra/Si composites towards practical anodes for commercial LIBs. The Gra/Si composites are prepared by exposing the mixture of pristine graphite flakes and Si nanoparticles to ultrasonication in water/surfactant solutions. The composite's major ingredients are found to be highly exfoliated graphene and crystal Si nanoparticles. As the anode in LIBs, the composite with ∼47.3 wt% Si shows improved electrochemical performance, with superiorly rate performance and a high reversible capacity of 700 mA h g⁻¹ after 100 cycles. The improved performance is ascribed to the graphene-derived 3D porous structure, which makes the Si nanoparticles well dispersed and buffers the volume change during the charge–discharge cycles. With respect to the simple and scalable liquid-exfoliated Gra/Si composite, the achieved performance here is fascinating for commercial LIBs.