Bionic Zwitterionic Osmolyte-Based Hydrogel Electrolyte for Achieving Highly Reversible Zinc-Metal Anodes

The rechargeable aqueous zinc ion hybrid supercapacitors (ZHSCs) with inherent safety, high ionic conductivity, and power density have attracted much attention for the development of integrated electronics. However, the dendrites growth and byproduct accumulation issues on zinc anodes severely restrict the rechargeability and utilization of ZHSCs. Herein, the zwitterionic proline/pectin/polyacrylamide/Zn(CF3SO3)2 hydrogel electrolyte (denoted as ZPPHE) with zwitterionic proline as permeant was constructed to effectively regulate the Zn deposition behavior, inhibit dendrite growth, and stabilize interfacial electrochemistry through multiple network interactions. The optimized hydrogel electrolyte shows a high ionic conductivity (2.63 S m-1) and a high Zn ion transference number (0.73) through this approach. Symmetric and asymmetric cells based on ZPPHE exhibit enhanced stability and reversibility with a remarkable operation time exceeding 450 h at 2 mA cm-2. Additionally, the quasi-solid-state ZHSCs based on ZPPHE demonstrate higher specific capacity and cycle stability, and the portable integrated self-powered device, equipped with an ionic skin (i-skin) and ZHSCs, can accurately detect physiological signals. This work provides practical approaches for the construction of highly rechargeable Zn anode and high-performance ZHSCs.