Fe3+/Fe2+ redox electrolyte for high-performance polyaniline/SnO2 supercapacitors
(Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education,
College of Chemistry, Xiangtan University, Xiangtan 411105, China)
College of Chemistry, Xiangtan University, Xiangtan 411105, China)
Abstract: The Fe3+/Fe2+ redox electrolyte for use in polyaniline/tin oxide (PANI/SnO2) supercapacitors was reported. The influences of redox electrolyte based on different Fe3+/Fe2+ ion pair concentrations in 1 mol/L H2SO4 solution on the pseudocapacitive behaviors of PANI/SnO2 supercapacitor were investigated. The electrochemical properties of the supercapacitor were studied by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) techniques. It is found that the performance of the supercapacitor is the best when the Fe3+/Fe2+ concentration is 0.4 mol/L and its initial specific capacitance is 1172 F/g at an applied current density of 1 A/g. The long-term cycling experiment shows good stability with the retention of initial capacitance values of 88% after 2000 galvanostatic cycles. The experimental results testify that using Fe3+/Fe2+ redox electrolyte has a good prospect for improving the performances of energy-storage devices.
Key words: polyaniline; tin oxide; iron ion; redox electrolyte; supercapacitors