Regenerated hydrogel electrolyte towards an all-gel supercapacitor

Abstract

Electrolyte regeneration is an important goal for environmental protection and sustainable development efforts. Herein, we report a facile strategy inspired by the transformation of edible dough from flour to regenerate hydrogel electrolytes from their dehydrated copolymer granules (CGs) via direct addition of water or salt solution. With the aid of heating, this procedure is efficient, relatively quick, and easily implemented. The dehydrated CGs are lightweight, reusable and stable under long-term storage. Even after 5 cycles of dehydration and regeneration, the regeneration efficiency of the hydrogel electrolytes, as evaluated based on retention of mechanical strength, is over 60%. The regenerated electrolytes possess considerable ionic conductivity, reprocessability, and 3D-printability. Furthermore, an all-gel supercapacitor assembled from the regenerated hydrogel electrolyte and activated carbon electrode with CGs as binder demonstrates excellent interfacial compatibility. The assembled all-gel supercapacitor can maintain 98.7% of its original specific capacitance after 100 bending tests, and can operate in a wide temperature range spanning from −15 to 60°C. This work may provide a new access to the development of renewable materials for various applications in the fields of intelligent devices, wearable electronics and soft robotics.