Aqueous asymmetric supercapacitor based on RuO2-WO3 electrodes

Abstract

Designing high-energy asymmetric supercapacitors(SC) with appropriate positive and negative electrodes is urgently required to expand their practical applicability. The redox-active materials are beneficial for high-energy SC applications because of their multiple oxidation states and higher energy storage capacity than the traditional carbon-based materials. In this work, for the first time, we have designed and developed high-energy aqueous asymmetric SC by combining hexagonal WO3 and hydrous RuO2 in a single cell. Initially, the hexagonal (h) WO3 and hydrous RuO2 is directly prepared on three-dimensional conducting carbon cloth. Because of their higher electrical conductivity, nanoporous surface morphology, and redox activity, the prepared hydrous RuO2 and WO3 exhibit excellent electrochemical features in the positive and negative potential window, respectively, with aqueous H2SO4 electrolyte. The assembled RuO2//h-WO3 asymmetric SC device exhibits outstanding electrochemical performance in an operating voltage window of 1.6 V, excellent cycling stability of ∼171.75% (after 6500 cycles), and energy density of 1.25 Wh/cm3 (16.92 W h/kg) at a power density of 40 W/cm3 (540 W/kg). These results show that redox-active materials can prominently enhance the energy storage capacity of SC than the traditional carbon-based asymmetric SCs.