Phase-Transitional Ionogel-Based Supercapacitors for a Selective Operation

High Resolution Image Download MS PowerPoint Slide As the demand for energy storage devices increases, the importance of electrolytes for supercapacitors (SCs) is further emphasized. However, since ions in electrolytes are always in an active state, it is difficult to store energy for a long time due to ion diffusion. Here, we have synthesized a phase-transitional ionogel and fabricated an SC based on the ionogel. The 1-ethyl-3-methylimidazolium nitrate ([EMIM] + [NO 3 ] − ) ionogel changes its phase from crystal to amorphous when the temperature was elevated above its phase transition temperature (∼44 °C). When the temperature is elevated from 25 to 45 °C, the resistivity of the gel is decreased from 2318.4 kΩ·cm to 43.2 Ω·cm. At the same time, the capacitance is boosted from 0.02 to 37.35 F g –1, and this change was repeatable. Furthermore, the SC exhibits an energy density of 7.77 Wh …