Bead-curtain shaped SiC@SiO2 core-shell nanowires with superior electrochemical properties for lithium-ion batteries

Silicon carbide (SiC) family is generally regarded as electrochemical inactive in lithium ion batteries (LIBs) and only a few literatures focused on its cycling property. In this work, bead-curtain shaped SiC@SiO2core-shellnanowires(SiC@SiO2-CSNWs) on graphite paper (GP) were fabricated by employing modified chemical vapor deposition method (CVD). After further hydrofluoric acid treatment, bare SiC nanowires (SiCNWs) on GP were also obtained for comparison. The as-prepared SiC@SiO2-CSNWs and SiCNWs were directly used as working electrodes without addition of binder or electron conductive material, which exhibited high specific capacities and good cycling stabilities. This could be ascribed to the unique nanowire structure, effectively buffering volume changes upon repeated alloying and de-alloying. Comparatively, SiC@SiO2-CSNWs presented much better electrochemical properties. Intensive transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectra analysis revealed that the SiO2 shell effectively separate the direct contact between active SiC and electrolyte, thus suppressed the fast growth of solid electrolyte interface (SEI) film in repeated cycling and stabilized the structure of active material.