A thermostable ionic liquid electrolyte for wide-temperature window supercapacitor. (1st December 2022)

• Record Type: Journal Article
• Authors: Guo, Qiyao; He, Benlin; Tan, Jin; Tang, Qunwei
• Is Part Of: Electrochimica acta. Volume 434(2022)
• Publication Date: 2022-12-01
• Subjects: High-temperature supercapacitors -- Electrolyte -- Capacitance -- Energy storage devices; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2022.141323
• Languages: English
• ISSNs: 0013-4686

Abstract

Abstract: The high-temperature supercapacitors have attracted growing attentions because the improved charge diffusion kinetics and ion conductivity of the electrolytes at elevated temperatures cause high capacitances. However, the state-of-the-art aqueous and/or anhydrous electrolytes always suffer from water or organic solvent evaporation, poor thermal stability and toxicity. We presented here a wide-temperature window supercapacitor made with an activated carbon electrode, a ceramic membrane separator as well as an electrolyte containing 1-methylimidazolium trifluoromethanesulfonate ([MI m ][OTf]) ionic liquid and ethylene glycol (EG) organic solution of potassium hydroxide (KOH) ([MI m ][OTf]/KOH/EG). By studying the impacts of temperature on capacitance, a maximized specific capacitance of 289 F g − 1 was achieved at 130 °C. Moreover, the champion supercapacitor presented an outstanding charging/discharging stability over 1500 cycles at 130 °C. The high capacitance along with long-term stability suggest that the ionic liquid electrolyte is prospective for wide-temperature window supercapacitors.