Ultrahigh Conductive and Stretchable Eutectogel Electrolyte for High-Voltage Flexible Antifreeze Quasi-solid-state Zinc-Ion Hybrid Supercapacitor

The aqueous zinc-ion hybrid supercapacitor (ZHSC) is a prospective energy storage device for next-generation wearable electronics due to its high safety, low cost, and high energy density. However, the preparation of gel electrolytes reported in the literature is complex and time-consuming, which limits their application in practice. Herein, we developed a robust and stretchable eutectogel electrolyte through a one-step gelation process in situ without introducing additional initiators and crosslinkers. The eutectogel electrolyte consists of ternary deep eutectic solvent (DES) based on Zn(ClO4)(2), AM(acrylamide), and H2O, among which ClO4- triggers the free-radical polymerization of AM monomer and Zn2+ cross-links the polymer chains. The prepared Zn-PAM-1 gel exhibits a high ionic conductivity of 51.7 mS cm(-1). Due to the inhibition of the free water activity in DES, the voltage window of the constructed flexible ZHSC was extended to 0-2.2 V. Moreover, the ZHSC in situ formed manifests a maximum energy density of 117.5 W h kg(-1) at a power density of 833.8 W kg(-1) and shows admirable cycling stability, retaining 87.6% of its capacitance after 4000 cycles. In addition, the supercapacitor possesses remarkable temperature stability within a range of -20 to 70 degrees C. Furthermore, the assembled flexible device illustrates favorable bendability from 0 degrees to 180 degrees without scarifying capacitance, displaying great promise as flexible wearable electronic devices. In summary, such a feasible approach provides further insight into the exploration of innovative eutectogel electrolyte systems for assembling quasi-solid-state pliable high energy storing devices.