Aqueous asymmetric supercapacitor based on RuO2-WO3 electrodes

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 WO 3 and hydrous RuO 2 in a single cell. Initially, the hexagonal (h) WO 3 and hydrous RuO 2 is directly prepared on three-dimensional conducting carbon cloth. Because of their higher electrical conductivity , nanoporous surface morphology , and redox activity, the prepared hydrous RuO 2 and WO 3 exhibit excellent electrochemical features in the positive and negative potential window, respectively, with aqueous H 2 SO 4 electrolyte. The assembled RuO 2 //h-WO 3 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/cm 3 (16.92 W h/kg) at a power density of 40 W/cm 3 (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.