Progress in the Preparation of Silicon/Carbon Composites for Use as Anodes in Lithium-Ion Batteries
Silicon/carbon (Si/C) composites are promising anode materials for high-energy-density lithium-ion batteries (LIBs) because they mitigate the severe volume expansion and poor electrical conductivity of pure silicon anodes. This review systematically summarizes the state-of-the-art preparation methods for Si/C composites, including ball milling, spray drying, electrostatic spinning, and chemical vapor deposition (CVD). Structural engineering strategies, such as carbon precursor coating, silicon-precursor-based wet chemistry, and silicon surface modification, are critically assessed for their effectiveness in enhancing electrical conductivity, buffering volume changes, and improving overall electrochemical performance. The review highlights that while Si offers a theoretical capacity of 4200 mAh g−1, far exceeding graphite's 372 mAh g−1, its practical application is hindered by capacity fading and low initial coulombic efficiency. The integration of carbon matrices not only provides mechanical flexibility but also facilitates electron transport. Key performance metrics from recent studies, including specific capacities exceeding 1000 mAh g−1 and improved cycling stability over hundreds of cycles, are discussed. The review also addresses the challenges of scalable production and cost-effectiveness, emphasizing the need for optimized precursor selection and processing parameters. Future research directions are proposed, focusing on the rational design of hierarchical structures and the development of novel binders to further enhance the long-term durability of Si/C anodes. This comprehensive overview serves as a valuable resource for researchers and engineers aiming to advance the commercialization of high-energy-density LIBs.