Effect of alkyl-chain length of imidazolium based ionic liquid on ion conducting and interfacial properties of organic electrolytes

Abstract

In this study the effect of imidazolium ionic liquid with a different alkyl side chain (ethyl, propyl and butyl) on ion conducting and interfacial properties of organic electrolytes against carbon electrode has been invested. The influence of electrochemical performances of imidazolium ionic liquids additives into organic solvent were examined by linear sweep voltammetry (LSV) cyclic voltammetry (CV), galvanostatic charge/discharge, and electrochemical impedance spectroscopy (EIS). The imidazolium ionic liquids with ethyl, propyl and butyl chains exhibited a variant electrochemical performance such an improved specific capacitance, low resistance, good rate capability and excellent cycle ability. Among the ionic liquids, BMImBF4 (10vol.%)—containing electrolyte presented the maximum specific capacitance (130.5Fg−1), capacitance retention (close to 80% after 1000 cycles) and low interfacial resistance of between electrolyte and electrode. It means that 10% BMImBF4 in EC/DME (1/1) can be a proper electrolyte of capacitors.