Designing ionophilic MXene-based organohydrogel electrolytes for high performance supercapacitor with wide-potential-window and anti-freezing properties
Ju‐Young Moon, Juyun Lee, Yun Chan Kang, Jong Hak Kim, Jung Tae Park, Seon Joon Kim
Abstract
Supercapacitors based on organohydrogel electrolytes can function at subzero temperatures and demonstrate a large potential range. However, for the development of next-generation energy-storage technologies, improvements in the ionic conductivity, mechanical strength, and flexibility of organohydrogel electrolytes are required. We employed Ti3C2Tx, an ionophilic MXene, as a nanofiller in this study to improve the ionic conductivity of organohydrogel electrolytes. Strong affinity for Li+ ions and good dispersibility in water/glycerol were obtained by the hydroxyl group's abundance on the surface of the ionophilic MXene. Due to the enhanced Li-ion hopping through the plentiful hydroxyl groups, an antifreezing supercapacitor based on the MXene/poly(vinyl alcohol) organohydrogel electrolyte (MXPVA-OHE) displayed a gravimetric capacitance as high as 19.84 F g−1 at room temperature and 3.49 F g−1 at - 20 °C. Due to their high ionic conductivity, wide potential window, and favorable post-freezing recyclability, MXPVA-OHE-based supercapacitors are thus excellent energy-storage devices.