A sandwich-like Si/SiC/nanographite sheet as a high performance anode for lithium-ion batteries.

Abstract

Silicon/carbon (Si/C) nanocomposite anodes have attracted great interest for their use in lithium-ion batteries (LIBs). However, Si nanoparticles are difficult to stabilize on a carbon surface. Herein, we solve this stabilization problem by designing a Si/silicon carbide/nanographite sheet (Si/SiC/NanoG) nanocomposite. The Si/SiC/NanoG nanocomposite is synthesized by the magnesium thermal reduction of a mixture of silica (SiO2) nanoparticles and NanoG at low temperature, which results in a sandwich-like structure in which the middle SiC layer serves as a linker to stabilize the Si nanoparticles on the surface of NanoGs. Electrochemical characterization shows that the Si/SiC/NanoG nanocomposite anode exhibits outstanding electrochemical performance (an initial reversible capacity of 1135.4 mA h g-1 and 80.4% capacity retention after 100 cycles at 100 mA g-1). This high capacity retention is due to the strong connection between Si and NanoG through the interfacial SiC layer, which buffers the volume changes during the Li-Si alloying-dealloying process. This research will contribute to the design of advanced Si/C anode materials of LIBs.