Implementing an in-situ carbon network in Si/reduced graphene oxide for high performance lithium-ion battery anodes

Abstract

Despite the intensive studies of combining silicon (Si) and reduced graphene oxide (rGO), the architecture of Si–rGO composites still needs to be improved to maintain better electrode structure integrity and stable solid electrolyte interphase (SEI) upon extensive cycling. Herein, a conductive and protective network with rGO and CVD-implemented carbon is constructed with silicon nanoparticles (Si NPs) embedded inside for the first time. Compared with the regular Si–rGO composite with only Si NPs wrapped by rGO, Si–rGO–C composite successfully improves the electrical conductivity and structure stability. In addition to the wrapping of rGO on Si NPs, the additional carbon layer on the partially exposed Si NPs provides extra protection from fracture during volume change and helps form a stable SEI layer. Carbon rods between rGO flakes function as conductive bridges, creating an effective conductive network on a macroscopic scale. The initial capacity of Si–rGO–C composite reaches 1139mAhg−1 and 894mAhg−1 at 0.1Ag−1 and 1C respectively, and retains 94% of its initial capacity after 300 cycles at 1C. The electrode is stabilized at 770mAhg−1 at 2C during rate performance testing.