Synthesis of size-controlled SiOC ceramic materials by silicone oil-based emulsion method for anodes in lithium-ion batteries

A submicron spherical silicon oxycarbide (SiOC) material for lithium-ion battery anodes was successfully synthesized by employing a facile synthetic strategy that used economical silicone oil as a starting material, an emulsion method, and the subsequent pyrolysis of silicone oil emulsion at 900 °C. Although most previous studies concerning silicone-oil-based SiOC exhibited irregular and uncontrollable size after synthesis, the developed emulsion-driven SiOC preparation achieved regular submicron spherical particles. Furthermore, the emulsifier used herein formed a thin carbon coating layer after the synthesis procedure and contributed to the electrochemical performance during battery operation. The spherical submicron size-controlled SiOC material had superior capacity retention compared to pristine SiOC obtained without the emulsion method, owing to the suppressed micro-cracks induced by accumulation of mechanical stress during repeated cycles and prevention of direct contact with the electrolyte by the thin carbon-coating layer.