Constructing Bi-continuous macroporous SiOC as high-performance lithium-ion battery anode

Silicon-based anodes are promising for high-energy density lithium-ion batteries (LIBs), while they are extremely constrained by serious volume expanding. Silicon oxycarbides (SiOC) can deliver milder volume change and acceptable theoretical capacity, but the electrochemical performance of most pure SiOC anodes is still limited by their volume expanding and poor electronic conductivity. Herein, a high-performance SiOC anode with bi-continuous macropores and robust skeletons derived from polyorganosiloxane aerogels was fabricated through a sol–gel method. The resultant SiOC material comprises free carbon phase, SiO4, SiO3C and SiO2C2 units. The specific capacity of bi-continuous macroporous SiOC anode can achieve 680 mAh g−1 after 350 cycles, possessing high reversibility and stability. The synergetic effect of robust skeletons, bi-continuous macropores, appropriate constitution of free carbon phase, SiO4 and SiO3C units endows the synthesized macroporous SiOC materials with such superior specific capacity and stable cycling performance. The bi-continuous macroporous SiOC with robust skeletons can provide a promising fundamental material to further achieve long-cycle SiOC anode materials.