Preparation and electrochemical performance of silicon@graphene aerogel composites for lithium-ion batteries

Abstract

Silicon/graphene composites are recently received more attention as promising negative electrode materials for the next generation lithium-ion batteries (LIBs) due to the synergistic effect of silicon and graphene. Silicon can provide high specific charge capacity, relatively low discharge potential, environmental compatibility and considerable abundance, while graphene exhibits excellent electrical conductivity, flexibility and large space for silicon expansion in the charge process. Herein, we adopted a simple hydrothermal method to obtain a silicon@graphene aerogel (Si@GA) composite with highly dispersible morphology and three-dimensional porous structure. The electrochemical characterizations prove that the Si@GA composite has excellent cycle performance and moderate rate performance during charge/discharge process. After 100 cycles, the specific charge capacity remains above 1330 mAh g−1 at 0.2 A g−1, and above 600 mAh g−1 at 2 A g−1, respectively. The excellent electrochemical performance of the composite may be attributed to the existence and specific structure of GA, which can improve the electrical conductivity and act as a buffer matrix to stabilize the composite electrode material. The composite material may promote the further application of silicon negative electrode materials.