Flexible Supercapacitor Based on Organohydrogel Electrolyte with Long-Term Anti-Freezing and Anti-Drying Property

Hydrogel electrolytes have spurred the development of flexible energy storage devices by endowing them with liquid-like ion transport and solid-like mechanical elasticity. However, traditional hydrogel electrolytes always lose these functions in climate change because the internal water undergoes freezing and/or dehydration. In this work, a flexible supercapacitor (OHEC) is assembled based on the organohydrogel electrolyte (OHE) and activated carbon electrode material. The OHE is composed of PAMPS/PAAm double-network hydrogel soaked from 4 m LiCl/ethylene glycol and exhibits good conductivities (1.9 and 22.9 mS cm⁻¹ at −20 and 25 °C, respectively). The OHEC exhibits broad temperature adaptability (from −20 to 80 °C) and extraordinary resistance to mechanical damage (above 100 kg crushing). The OHEC avoids the polarization at low temperatures and retains 77.8% capacitance retention after storage at −20 °C for 30 days. Without extra sealed packaging, the OHEC maintains remarkable cycling stability (only 8.7% capacitance decay after 10 000 cycles) and retains 77.3% capacitance at 80 °C after 56 h. The outstanding anti-drying performance and improved interfacial compatibility of OHEC account for the good durability in the high-temperature environments. Additionally, other salts (such as LiClO₄, NaCl, and KCl) with favorable solubility in ethylene glycol can also serve in OHEs for wide temperature range supercapacitors.