Low-Temperature-Resistant Flexible Solid Supercapacitors Based on Organohydrogel Electrolytes and Microvoid-Incorporated Reduced Graphene Oxide Electrodes

Maintaining enough flexibility and satisfied electrochemical performance simultaneously at subzero temperatures is still challengeable for flexible solid supercapacitors. In the present work, by adopting an organohydrogel electrolyte and reduced graphene oxide (rGO) films with microvoids serving as electrodes, a supercapacitor, which could be steadily operated down to −60 °C, has been obtained and has shown excellent low-temperature tolerance. The organohydrogel electrolyte consists of LiCl in glycerol/water solution containing polyvinyl alcohol, exhibiting excellent flexibility at −60 °C. Due to the introduction of micropores between rGO sheets, the porous membrane can be folded even in liquid nitrogen. Combining the rGO electrodes with the organohydrogel electrolyte, the maximum voltage of the present supercapacitor could be extended to 2.0 V, and a capacitance of 7.73 F·g–1 at −60 °C could be achieved. After 5000 charge/discharge cycles at −20 °C, the capacitance retention rate is 87.5%. The excellent flexibility and low-temperature resistance of the current supercapacitor pave a novel way for developing compression-resistant electronic samples compatible with a low-temperature environment.