Self-Healing Hydrogels with Triple Dynamic Bond Synergy for All-Gel Supercapacitors

Developing a hydrogel with outstanding self-healing properties, favorable electrical conductivity, and decent mechanical properties holds substantial significance for promoting flexible electronic devices and facilitating green, environmentally sustainable development. However, realizing both a rapid self-healing rate and superior self-healing efficiency of hydrogels simultaneously remains a challenge at present. Herein, a self-healing hydrogel electrolyte incorporating triple dynamic bonding was synthesized by acrylic acid (AA) and methacrylamide (MAm) as monomers through one-step thermal radical polymerization, which exhibited excellent self-healing properties, achieving complete healing within 5 min. For the purpose of improving the electrical conductivity of hydrogel electrolytes, NaCl was added as an auxiliary conducting substance to increase its conductivity by 187.2% (from 0.335 to 0.612 S/m) without compromising the self-healing property. This hydrogel electrolyte was assembled into an all-gel supercapacitor (AGS), followed by relevant electrochemical tests. The all-gel supercapacitor exhibited strong interfacial adhesion (73.97 kPa) and sound electrochemical performance (specific capacitance was 3.7 F g–1 at 0.05 A g–1 and energy density was 82.2 mWh kg–1 at 20 W kg–1). Meanwhile, the all-gel supercapacitors could retain over 77.78% of their initial capacitance after 3000 consecutive charge–discharge cycles, and the Coulombic efficiency was also retained at 97.2%. This self-healing hydrogel electrolyte demonstrates promising application potential in the field of flexible energy storage components.