Surface modification strategies for silicon based anodes coated with polymer-derived carbon source

By forming alloys with Li ions, silicon (Si) can possess an energy capacity ten times that of graphite anodes, making it a promising candidate for the next generation anode materials for lithium-ion batteries. However, the large volumetric changes of Si during the lithiation/delithiation process result in unstable electrochemical cycling performance, and the deficiencies in electrical and ionic conductivity limit its rate performance, thereby constraining the large-scale application of Si-based anode. Due to its strong interaction with Si particles and its convenience in constructing doped carbon layers and carbon layers with special structures, polymers are regarded as low-cost (for example, the price of lignin is as low as 200∼600 $/ton) and effective carbon sources to prepare core-shell structured Si@C composite materials and optimize the shortcomings of Si-based anodes. In this review, we first discuss surface modification methods for Si particles aimed at enhancing the adhesion to polymers and effectively improving the dispersibility of Si nanoparticles in polymers. Subsequently, the roles and methods for improving the electronic/ionic conductivity and structural stability of carbon layers, including doping and the construction of various special structures, are summarized and compared. These advancements position Si@C composites as viable candidates for next-generation high-energy batteries. Finally, the prospects for Si anodes coated with polymer-derived carbon layers are proposed.