Construction of Protein-Like Helical-Entangled Structure in Lithium-Ion Silicon Anode Binders via Helical Recombination and Hofmeister Effect.

In this study, a novel gelatin-xanthan gum composite binder is successfully developed with a protein-like helical-entangled network structure through thermo-responsive and Hofmeister effect to improve the cycling stability of silicon anodes in lithium-ion batteries. As the temperature changes, the molecular chains of xanthan gum and gelatin undergo de-helixing, intertwining, and co-helixing, ultimately self-assembling into a protein-like spatial structure. Furthermore, immersing in Hofmeister salt solution enhances the degree of helical entanglement, significantly improving strength and toughness. This novel helical-entangled structure absorbs and dissipates the stress and strain caused by silicon volume expansion through repeated bending, twisting, and stretching, similar to protein spatial structures, thereby maintaining the integrity of the silicon anode and enhancing its cycling stability. The silicon anode with the optimized binder exhibits high initial Coulombic efficiency, favorable rate performance, and long-term cycling stability. At a current density of 0.5 A g⁻¹, the silicon anode has a specific capacity of 1779.8 mAh g⁻¹ after 300 cycles, with a capacity retention rate of 80.65%. This study demonstrates the feasibility of natural polymers forming complex 3D network structures through self-assembly and intermolecular forces, providing a new approach for the design of silicon anode binders.