Conducting and interface characterization of carbonate-type organic electrolytes containing EMImBF4 as an additive against activated carbon electrode

Abstract

Carbonate-type organic electrolytes were prepared using propylene carbonate (PC) and di­methyl carbonate (DMC) as a solvent, quaternary ammonium salts, and by adding different contents of 1-ethyl-3-methyl imidazolium tetrafluoroborate (EMImBF4). Cyclic voltammetry and linear sweep voltammetry were performed to analyze conducting behaviors. The surface characterizations were analyzed by scanning electron microscopy method and X-ray photo­electron spectroscopy. From the experimental results, increasing the EMImBF4 content in­creased the ionic conductivity and reduced bulk resistance and interfacial resistance. In par­ticular, after adding 15 vol% EMImBF4 in 0.2 M SBPBF4 PC/DMC electrolyte, the organic electrolyte showed superior capacitance and interfacial resistance. However, when EMImBF4 content exceeded 15 vol%, the capacitance was saturated and the voltage range decreased.