Protic ionic liquid as electrolyte for high-densities electrochemical double layer capacitors with activated carbon electrode material

Prior to realizing grid-scale applications of the energy storage devices, there remain several key issues including the development of low-cost, high-performance materials and electrolytes which are environmentally friendly and compatibles with low-temperature and large-scale processing. The present work reports the preparation, characterization, and comparative application of two PILs namely, diisoprpylethylammonium methanesulfonate, [DIPEA][MeSO3], and pyrrolidinium methanesulfonate, [Pyrr][MeSO3], in mixture with water as electrolyte for supercapacitor applications. Different electrochemical measurements like cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge–discharge were conducted to study the performance of these aqueous solutions as supercapacitors with activated carbon electrode. From this work, good specific capacitances up to 102 F g−1 have been observed even at high-rate cyclability, as well as an increase of the specific power close to 13.9 kW kg−1 at high current density of 15 A g−1.

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► Preparation, characterization, and comparative application of two protic ionic liquids as electrolytes for supercapacitors.
► The conductivity of aqueous solution of PILs increases with the temperature, up to 65.8 mS cm−1 for [DIPEA][MeSO3] and up to 120 mS cm−1 for [Pyrr][MeSO3].
► Good specific capacitances have been observed even at high-rate cyclability, v = 400 mV s−1.
► High specific power close to 13.9 kW kg−1 have observed at high current density up to 15 A g−1.