Cellulose-based organohydrogels for energy storage achieving high conductivity and wide temperature tolerance from -40 °C to 100 °C.

In recent years, energy shortage and climate change have been increasingly serious, so that cellulose-based hydrogel solid electrolytes hold great promise for safe, sustainable and efficient energy storage materials. However, it is challengeable to simultaneously achieve high conductivity, excellent mechanical properties and wide temperature range of hydrogel solid electrolytes. Here, carboxymethylcellulose (CMC) was introduced for constructing ion migration channels and polymer skeleton of dual-network organohydrogels. Meanwhile, 2-urea-4[1H]-pyrimidine methyl methacrylate (UPyMA) network, which interpenetrated with CMC, imparted CMC-based organohydrogels with enhanced conductivity and mechanical properties. The ionic conductivity achieved as remarkable as 95.72 mS cm, providing the assembled flexible supercapacitor with outstanding specific capacitance of 350.68 mF cm, outputting energy density of 93.46 μWh cm at power density of 0.192 mW cm. Furthermore, the flexible supercapacitor performed stably under bending and multiple cyclic compression. Attributing to the introduction of DMSO, the capacitance retained 65 % and 121 % comparing to that at room temperature under -40 °C and 100 °C, respectively. This work presents a novel strategy for fabricating high-performance, wide-temperature-tolerant flexible supercapacitors, which offers insights for advancing next-generation flexible energy storage technologies.