Anchorage-Capture Dual Mechanism in a Biomass-Derived Hydrogel Electrolyte for Dendrite-Free Aqueous Zinc Ion Batteries

The design of biomass-derived polymer electrolytes with integrated multifunctionality represents a key strategy for sustainable energy storage devices. Here, we report a fully biomass-derived dual-network hydrogel electrolyte fabricated by combining Pectin (PC) and Chitosan (CTS), two naturally abundant polysaccharides. The Pectin/Chitosan dual-network hydrogel electrolyte (PC/CTS) forms a robust physically crosslinked network through electrostatic interactions between the carboxyl groups of PC and the amino groups of CTS, reinforced by dense hydrogen bonding and amide crosslinks, yielding a tensile strength of 77.76 MPa. The abundant polar functional groups of the dual polymer network serve a synergistic dual function: the amino groups of CTS preferentially adsorb onto the zinc anode surface (adsorption energy: −1.24 eV), forming a dynamic protective interphase, while the carboxyl groups of PC coordinate with Zn2+ (binding energy: −0.86 eV), reconstituting the solvation sheath and guiding uniform ion flux. This anchorage-capture mechanism, enabled by the molecular design of the polymer network, effectively suppresses dendrite growth, hydrogen evolution, and parasitic side reactions. Consequently, the PC/CTS electrolyte enables stable Zn//Zn cycling for 3350 h, 99.5% average Coulombic efficiency (CE) over 780 Zn//Cu cycles (at 5 mA cm−2 and 1 mAh cm−2), and 63.8% capacity retention after 500 cycles in Zn//MnO2 full cells. This work demonstrates that rational engineering of natural polymer networks can simultaneously address electrode stability challenges in aqueous batteries, offering a sustainable materials platform for next-generation energy storage devices.