High-performance conductive eutectogel synthesized by carboxymethyl cellulose-enhanced physicochemical dual network for supercapacitors and wearable electronic devices.

Hydrogels have garnered considerable attention in wearable devices due to their tunable mechanical properties. However, their applications are constrained by limited conductivity and inadequate freeze-resistance. In this study, we develop a physical-chemical dual network eutectogel (PECA/CMCX) through a synergistic enhancement strategy combining the multiple hydrogen bonds of carboxymethyl cellulose sodium (CMC) with metal-ion coordination within a deep eutectic solvent (DES). The eutectogel incorporates a physically cross-linked CMC network with a chemically cross-linked polyacrylamide (PAM) network via multiple non-covalent interactions (e. g., hydrogen bonds) and covalent bonds formed through free-radical polymerization. PECA/CMC1.35 eutectogel exhibits superior mechanical properties, a fracture toughness (29.22 kJ·m-3) and a high tensile stress (23.8 kPa). Owing to the carboxyl-metal ions coordination and the freezing-point depression effect of DES, the eutectogel maintains a high conductivity of 0.35 S·m-1 at -20 °C. When employed as an electrolyte in a supercapacitor, it exhibits stable cycling performance, retaining 79.4% of its initial capacitance and a Coulombic efficiency of 92.3% after 2000 cycles. As a strain sensor, the eutectogel achieves a gauge factor (GF) of 1.06 over a range of 40-200%. This work introduces a sustainable synergistic design strategy for multifunctional eutectogel suitable for flexible electronic devices under extreme conditions.