Application of imidazolium-based ionic liquids as electrolytes for supercapacitors with superior performance at a wide temperature range.

A potential new family of adaptable, ecologically acceptable solvent systems are ionic liquids (ILs). This study is the first to offer a new method for using imidazolium-based ILs as affordable, anti-corrosion electrolytes for activated carbon-based electrochemical capacitors (ECs). In this context, the ILs 1-hexyl 3-methylimidazolium bromide ([HMIM]Br) and 1-ethyl 3-methylimidazolium ethyl sulfate ([EMIM]ES) were synthesized. In the region of ambient temperature up to 105 °C, significant features including viscosity, electrical conductivity, and electrochemical tests were investigated. The symmetric ECs in imidazolium-based electrolytes, which display exceptional electrochemical stability at a maximum voltage of up to 3.5 V, deliver high energy. At room temperature, the specific capacitance of the electrolyte containing IL [HMIM]Br drops to 87 F g−1 (with an energy density of 37 Wh kg−1) from 174 F g−1 (with an energy density of 74 Wh kg−1) under 105 °C. In addition, the supercapacitor made using IL [HMIM]Br retained 90.6% of its capacity up to 10,000 cycles at 105 °C. The findings have significant ramifications for extending the use of eco-friendly, non-toxic, and affordable electrolytes for high-performance ECs with broad voltage windows and improved longevity. [ABSTRACT FROM AUTHOR]