Microgel-enhanced thermal-sensitive hydrogel electrolyte enables active heat management, controllable energy storage and mechanical flexibility of supercapacitors

Thermal runaway is a critical issue in energy storage process, leading to damage even failure of energy storage devices. Herein, active heat management, controllable energy storage and mechanical flexibility of supercapacitors are achieved by utilizing microgel-enhanced thermal-sensitive hydrogels as electrolytes. Because of the improved thermal sensitivity of microgel-enhanced hydrogel electrolyte, heat can be efficiently consumed by volume phase transition process, and meanwhile the energy storage process is also weakened by slowing down the ion transport. Reversibly controlled energy storage is also demonstrated in such supercapacitors. By varying temperature below and above volume phase transition temperature (VPTT) of hydrogel electrolytes, the specific capacitance is switched between 124 mF cm−2 and 9 mF cm−2. Moreover, the hydrogel electrolytes also endow such supercapacitors mechanical flexibility and stable charge–discharge under a bending angle from 0 to 180° has been demonstrated. Overall, this work has provided a new clue to construct intelligent hydrogel devices by elegant structure design.