Interpenetrating Polymer Network Eutectogels Derived From Polymerizable Deep Eutectic Solvents for Low-Temperature Supercapacitors.

This study developed a polymerizable deep eutectic solvent (PDES) system composed of H2O, choline chloride, and acrylic acid, which exhibited a freezing point as low as -57.2 °C. By introducing sodium acetate and carrying out in situ polymerization within a polyacrylamide hydrogel, a high-performance eutectogel with an interpenetrating polymer network (IPN) structure was constructed. The optimized IPN eutectogel demonstrates outstanding overall properties, including high mechanical strength (tensile stress up to 97.2 kPa) and toughness (fracture elongation of 235%), while maintaining high ionic conductivity (21.4 mS cm-1 at 25°C) across a broad temperature range (-40 to 60°C). Supercapacitors using this eutectogel operate effectively within a 1.2 V voltage window and exhibit ideal electric double-layer capacitive behavior. They achieve a maximum energy density of 7.10 Wh kg-1, retain 80% of the initial capacitance after 10,000 cycles, and show stable performance under bending, damage, and low-temperature (-30 °C) conditions. These results underscore the material's strong potential for use in flexible and low-temperature energy storage devices.