A Low‐Temperature‐Tolerant Gel Polymer Electrolyte With Dual Cations for Flexible Zinc‐Ion Hybrid Supercapacitors

ABSTRACT Flexible energy storage devices face critical challenges from the reduction of ionic conductivity and the degradation of mechanical properties at low temperatures. To overcome this, our study develops a low‐temperature‐tolerant flexible zinc‐ion hybrid supercapacitor (ZIHS) using a synergistic dual‐network gel polymer electrolyte (GPE) and dual‐cation transport strategy. The GPE features a physicochemical dual‐network hydrogel with dual‐cationic (Zn 2+ /NH 4 + ) electrolyte: (1) A reversible physical network of polyvinyl alcohol and κ‐carrageenan crosslinked via hydrogen bonding, providing fatigue resistance; (2) A covalently crosslinked polyacrylamide network ensuring structural stability. The GPE demonstrates a low freezing point of −90.5°C and a high ionic conductivity (53.2 mS cm −1 at 25°C). The GPE exhibits exceptional flexibility, retaining practicality under bending/twisting at −20°C. The ZIHS delivers a specific capacitance of 178.69 F g −1 at 0.5 A g −1 , an energy density of 56.27 Wh·kg −1 , and 93.5% capacitance retention after 5300 cycles. This work provides a paradigm for robust, freeze‐resistant wearable electronics under low temperatures.