Manipulating Oxidation of Silicon with Fresh Surface Enabling Stable Battery Anode

Abstract

Silicon (Si)-based material is a promising anode material for next-generation lithium-ion batteries (LIBs). Herein, we report the fabrication of a silicon oxide-carbon (SiO_<i>x</i>/C) nanocomposite through the reaction between silicon particles with fresh surface and H₂O in a mild hydrothermal condition, as well as conducting carbon coating synchronously. We found that controllable oxidation could be realized for Si particles to produce uniform SiO_<i>x</i> after the removal of the native passivation layer. The uniform oxidation and conductive coating offered the as-fabricated SiO_<i>x</i>/C composite good stability at both particle and electrode level over electrochemical cycling. The as-fabricated SiO_<i>x</i>/C composite delivered a high reversible capacity of 1133 mAh g^-1 at 0.5 A g^-1 with 89.1% capacity retention after 200 cycles. With 15 wt % SiO_<i>x</i>/C composite, graphite-SiO_<i>x</i>/C hybrid electrode displayed a high reversible specific capacity of 496 mAh g^-1 and stable electrochemical cycling with a capacity retention of 90.1% for 100 cycles.