A low-cost and high-capacity SiOx/C@graphite hybrid as an advanced anode for high-power lithium-ion batteries

Abstract

Silicon suboxide (SiOx) is one of the most promising anodes for the next-generation high-power lithium-ion batteries because of its higher lithium storage capacity than current commercial graphite, relatively smaller volume variations than pure silicon, and appropriate working potential. However, the high cost, poor cycling stability, and rate capability hampered its industrial applications due to its complex production process, volume changes during Li+ insertion/extraction, and low conductivity. Herein, a low-cost and high-capacity SiOx/C@graphite (SCG) hybrid was designed and synthesized by a facile one-pot carbonization/ hydrogen reduction process of the rice husk and graphite. As an advanced anode for lithium-ion batteries, the SiOx/C@graphite hybrid delivers a high reversible capacity with significantly enhanced cycling stability (842 mAh g-1 after 300 cycles at 0.5 A g-1) and rate capability (562 mAh g-1 after 300 cycles at 1 A g-1). The great improvement in performances could be attributed to the positive synergistic effect of SiOx nanoparticles as lithium storage active materials, the in situ-formed carbon matrix network derived from biomass functioning as an efficient three-dimensional conductive network and spacer to improve the rate capability and buffer the volume changes, and graphite as a conductor to further improve the rate capabilities and cycling stability by increasing the conductivity. The low-cost and high-capacity SCG derived from rice husk synthesized by a facile, scalable synthetic method turns out to be a promising anode for the next-generation high-power lithium-ion batteries.