A flexible ternary oxide based solid-state supercapacitor with excellent rate capability

Abstract

A porous vanadium doped-zinc–nickel–cobalt ternary oxide (VZnNiCo) nanostructure is presented for a high performance flexible supercapacitor (SC). The symmetric solid-state SC demonstrated a remarkable enhancement in the capacitive response as compared to SCs based on its individual oxide constituents e.g. NiCo₂O₄//NiCo₂O₄ or ZnNiCo//ZnNiCo. A synergistic redox reaction from all the ions was offered to increase the capacitive response and moreover, direct growth of the unique porous nanostructure on a flexible current collector exhibited excellent ion-diffusion efficiency with a high electrochemically active surface area. The flexible SC demonstrated excellent capacitive response stability towards large mechanical deformations for a much higher scan rate up to 5000 mV s⁻¹ in addition to high cycling stability. Hence, the present work opens novel avenues towards exploiting hybrid flexible energy storage devices that are mechanically robust with a highly stable capacitive ability at a much higher scan rate.