Multifunctional Polymer Binders for High-Capacity Silicon Anodes: Modification Strategies, Interface Chemistry, and Structural Design

Abstract

Silicon (Si) is considered one of the most promising anode materials due to its high theoretical specific capacity (4200 mah g⁻¹), abundant availability (second most abundant element in the Earth's crust), low operating potential (<0.4 V vs. Li/Li⁺), and environmental sustainability. Typically, Si anode undergoes a severe volume change (400%) during battery cycling, which leads to crushing of the active material, infinite growth of the solid electrolyte interface film (SEI), contact failure between the active material and the collector, and low initial coulombic efficiency (ICE). Therefore, the binder used for silicon anodes must maintain intimate contact between the components of the electrode to maintain the electron-ion transport channels within the electrode. This study reviews recent applications of polymer binders in silicon anodes, focusing on the design of the binder network structure, the interfacial chemistry of functional groups, and the synthesis strategies for multifunctional polymer binders. Additionally, the development of new multifunctional binders, including conductive and self-healing binders, is extensively discussed. We hope that this summary of multifunctional binders will guide the design of innovative binders.