Silicon oxycarbide-based composites anodes for lithium-ion batteries: Retrospect and prospect

Silicon oxycarbide (SiOC), a polymer-derived ceramic characterized by high theoretical capacity, small volume expansion, and superior electro-chemo-mechanical stability, has attracted considerable attention as a particularly promising alternative to Si-based and carbonaceous anodes for next-generation lithium-ion batteries (LIBs). However, its low effective capacity, inferior initial Coulombic efficiency, and poor electrical conductivity pose significant challenges for practical applications. Notably, by integrating composition effect and design flexibility, SiOC-based composites provide a revolutionary new paradigm for overcoming the performance bottlenecks and practicality problems of SiOC. The past nearly two decades has witnessed numerous elaborately designed and ingeniously engineered SiOC-based composites for anodes in LIBs. In this review, the fundamental design concept of advanced SiOC-based composite anodes with boosted lithium storage properties is first introduced. Then, we systematically classify and summarize the latest research progress in SiOC-based composite anodes from the perspective of materials system, dividing them into SiOC/C composites, SiOC/Si composites, and SiOC/metal composites, with a focused discussion on their design schemes, preparation approaches, and lithium storage performance. Finally, the remaining key challenges are outlined, and future research agenda is proposed. We believe that this review provides an actionable roadmap for unlocking the full potential of SiOC-based composite anodes in the next-generation high-energy LIBs.