A High-Entropy Hydrogel Electrolyte Generated by Intrinsically Disordered Polymer Segments for Efficient Zinc Metal...

Hydrogel electrolytes hold promise in enabling aqueous zinc metal batteries (ZMBs) as a sustainable energy storage technology, but they still suffer from the trade-off between high ion conduction and electrochemical stability. High-entropy engineering strategies are powerful in unlocking new regimes in energy storage, yet this paradigm has rarely been reported in hydrogel electrolytes. Herein, we report a proof-of-concept high-entropy hydrogel electrolyte (HEHE) that integrates three ionic monomers to maximize compositional diversity and entropic stabilization. Multimodal experimental characterizations and theoretical simulations reveal that the HEHE can promote the formation of entropically stabilized ion transport pathways, and minimize water reactivity and contact ion pairing, thereby enabling selective cation conduction, uniform ionic flux, low-energy interfacial desolvation, and crystallographic zinc deposition. The resulting HEHE circumvents the aforementioned dilemma, achieving essential electrochemical properties far exceeding those of the low-entropy counterpart, while enabling full ZMBs to work stably at a practically high areal capacity of 3.2 mAh cm^-2. Such a HEHE uniquely orchestrates four entropy contributions within the gel matrix, and the applicability of this strategy is corroborated in parallel hydrogel electrolytes. This work establishes entropy-driven design as a generalizable approach for soft ion conductors, expanding the scope of high-entropy materials into aqueous batteries and beyond.