From Physical Cross‐Linking to Tailored Phosphorylation: Unlocking High‐Performance and Biocompatible Xanthan‐Konjac Hydrogels for Zinc‐Ion Batteries

Abstract Natural polymer‐based hydrogel electrolytes, though biocompatible and cost‐effective, often exhibit poor mechanical strength and ionic conductivity, limiting their use in high‐performance energy storage. Phos‐XK, a novel hydrogel electrolyte derived from xanthan gum (XG) and konjac glucomannan (KGM), has been developed via physical cross‐linking and targeted phosphorylation. Specifically, physical cross‐linking forms a robust 3D network that provides a stable structural foundation. Building on this, the phosphorylation process introduces phosphate monoesters (MPE) and diesters (DPE) in a precisely controlled ratio. MPE groups enhance ionic conductivity by facilitating Zn ²⁺ desolvation and ion migration, while DPE strengthens mechanical integrity through enhanced cross‐linking. These distinct roles of MPE and DPE are confirmed through both theoretical calculations and experimental results. Optimizing the phosphorylation ratio achieves a balance between mechanical strength (2.524 MPa) and ionic conductivity (20.72 mS cm ⁻¹ ), resulting in remarkable electrochemical performance, including an extended cycle life exceeding 3000 h and a high Coulombic efficiency of 99.45% in Zn//Cu batteries. Moreover, Phos‐XK is biocompatible and biodegradable, ideal for sustainable energy storage. This work highlights the potential of bio‐based materials to overcome the limitations of traditional hydrogel electrolytes and stresses the importance of molecular engineering in achieving high‐performance, eco‐friendly energy storage.