High performance supercapattery using zinc oxide-carbon black hybrid material in aqueous salt electrolyte

This work demonstrates the development of a binder-free, stable, cost-effective and scalable supercapattery using Zinc Oxide and Carbon Black (ZnO-CB) hybrid material as the cathode. Herein, we have employed aluminium foil as the anode free current collector and aqueous NaCl as the electrolyte to fabricate the device which functions in a wide electrochemical potential window of 2 V. Pseudocapacitive charge storage linked to reversible surface redox processes of ZnO in aqueous electrolyte and electric double-layer capacitance caused by Na + /Cl − ion adsorption combines to provide supercapattery behaviour. Thus, the as prepared supercapattery device with 2 wt% ZnO with uniform morphology offers a specific capacity (C s ) of 117.89 C/g with a high energy density of 65.49 Wh/kg and an ultrahigh power density of 1544 W/kg even at a current density of 10 A/g, surpassing many reported supercapattery. Further, the device shows excellent capacity retention of nearly 100% of its initial capacity after 1000 charge discharge cycles.