Self-healing multifunctional binder for silicon anodes with dynamic crosslinking and solvent coordination regulation

Severe volume changes and poor electrochemical performance are key barriers to the practical use of silicon anodes. In this study, a self-healing, multifunctional supramolecular binder system was introduced, which combines polymers, ionic liquids, and halometals to achieve dynamic cross linking during volume changes. The addition of specific halometals can adjust the Li⁺ solvation structure and energy, promoting the formation of a stable solid electrolyte interface (SEI) rich in LiF and facilitating Li⁺ desolvation. After 200 cycles, the Si@BF binder (with both ionic liquid and halometal) showed no cracks, indicating excellent structural stability. Additionally, Si||LiFePO₄ (LFP) full-cell tests at 5 C rate reveal drastic differences: The unmodified binder (the pristine Si) exhibits nearly 0% capacity retention after 400 cycles, the ionic liquid-modified system (Si@B) maintains 11.58%, while Si@BF achieves a remarkable 90.92% retention. Notably, Si@BF retains 78.72% capacity even after 800 cycles. This study offers new insights into dynamic cross-linking systems and solvation-structure regulation, providing references for developing advanced lithium-ion batteries with better performance.