Silicon embedded into graphite by van der Waals force for high-performance Li-ion batteries

Abstract

Combining silicon nanoparticles (Si NPs) with graphite is considered as a promising strategy to develop commercial anodes for high-energy lithium-ion batteries (LIBs). Nevertheless, the challenge lies in achieving homogeneous dispersion while ensuring the Si NPs make effective electrical contact within the graphite matrix. Herein, a scalable double-roll milling process is developed to uniformly disperse and embed Si NPs within graphite sheets (GS), yielding the E-Si-GS composite. The mechanical rolling force enables effective interlayer confinement of Si NPs, which are firmly anchored to the GS via van der Waals interactions and amorphous carbon bridging. Meanwhile, the preconstructed internal voids between GS and Si NPs efficiently accommodate the volume expansion of Si NPs and promote electrolyte infiltration. Benefiting from these structural merits, the E-Si-GS anode delivers excellent rate capability and long-term cycling stability, achieving a capacity retention of 89.3% over 800 cycles at 3 C. When matched with a LiFePO4 cathode, the assembled full cell exhibits a highcapacity retention of 95.7% after 100 cycles at 1 C. Furthermore, high-mass-loading testing, pouch cell fabrication, and LED lighting demonstrations further verify the promising practical applicability of the E-Si-GS anode.