Investigation of Dual Redox Electrolyte based on 1,1′-Dimethyl-4,4′-bipyridinium Diiodide for Superior Supercapacitors

Abstract

Development of more energy-efficient storage systems is required to meet the growing worldwide demand for energy. Redox electrolytes are clearly a long-term choice for high-energy-density supercapacitor applications in near future. Herein, the synthesis and electrochemical investigations of a dual redox electrolyte based on 1,1′-dimethyl-4,4′-bipyridinium diiodide as high-performance supercapacitors are reported. Previous researchers have focused on methyl viologen with reduced and oxidized redox bromide additive electrolytes at the negative and positive electrodes, respectively. In this work, by replacing iodine with bromine to solve current collector issues, reduce corrosion and contribute to the low toxic impact on the environment is investigated. The electrochemical results revealed that the maximum energy density of 63 Wh kg^-1 and the capacity of 514 F g^-1 were achieved with a modest concentration of additives. Exclusively, iodide anion boosted the stability by 95% and reduced deterioration until 10,000 cycles. This ground-breaking idea addresses the development of high-energy-density supercapacitors as well as a viable energy storage approach.