Engineering self-healing cellulose-reinforced organohydrogel electrolytes for flexible foldable capacitors with low temperature adaptability

Hydrogel-based capacitors have garnered significant interest due to their diverse applications and alignment with the principles of green chemistry. An antifreeze cellulose-based hydrogel with excellent mechanical, conductive, and self-healing properties was successfully prepared in this study using a simple method. The incorporation of TA@WSCA (tannic acid-coated water-soluble cellulose acetate) and Al3+ as dual crosslinkers in the hydrogel markedly enhances both its mechanical and self-healing properties. The hydrogel exhibits impressive tensile strength and toughness, reaching 932.2 kPa and 3.294 MJ/m3, respectively. Remarkably, it maintains excellent flexibility and conductivity within the temperature range of −40°C to 25°C. In addition, the supercapacitor composed of TA@WSCA-Al3+-PAA hydrogels has a capacitance of up to 234 F/g and an extremely long cycle life. After 10,000 cycles of charging and discharging, its capacitor retention rate can still reach more than 90%. In conclusion, this study introduces a straightforward approach for fabricating flexible supercapacitors with multifunctionality, providing innovative insights for the advancement of wearable devices.