Dynamic Hydrogen Bonds and Al 3+ Coordination for High-Performance Silicon Anodes

Binders typically interact with surface –OH groups on silicon anodes via van der Waals forces, hydrogen bonds, or covalent bonds. However, poor mechanical flexibility leads to volume expansion of silicon anodes and degraded electrochemical performance. Therefore, this work employs an aqueous solution blending method to integrate sodium alginate, β -cyclodextrin, and Al 3+ ions, constructing a dual-cross-linked network binder featuring metal coordination bonds and dynamic hydrogen bonds. The prepared Alg- β -Al composite binder exhibits high viscosity, moderate modulus, strong electrode detachment force, and excellent wrinkle resistance. Silicon anodes constructed with this binder demonstrate high initial coulombic efficiency (93.2%), outstanding rate performance, and long-term cycling stability. After 200 cycles at 0.2 A g −1 , the reversible capacity of Si@Alg- β -Al retained 1560.8 mAh g −1 , and even after 800 cycles at 0.5 A g −1 , it maintained a reversible capacity of 1650 mAh g −1 . Furthermore, it effectively buffers silicon volume expansion, maintains electrode structural integrity, promotes lithium ion transport, and induces the formation of a stable solid electrolyte inter-phase (SEI) film. This work provides new insights into the balance between rigidity and flexibility in high-performance binders and their electrochemical performance.