Plant growth–inspired design of high-performance composite electrode nanostructures for supercapacitors

Abstract

A strategy inspired by plant growth was applied as a novel and facile way to fabricate nanoscale composites for high-performance electrodes employed in supercapacitors. A binder-free cactus-like nanostructure CoNiO2@Co3O4@Co2N grown on N-doped reduced graphene oxide (rGO)-wrapped nickel foam, in which the N-doped rGO sheet acts as the ground, providing active sites for the composite to grow, and the nickel foam acts as the root system, providing both Ni ions to form the bimetal oxide CoNiO2 and storage for the electrolyte ions, was designed. As the active material, the nanostructured CoNiO2@Co3O4@Co2N not only provides more ion-accessible surfaces but also contributes its battery-mimicking faradaic reaction to the high electrochemical performance of the as-prepared electrode. The synergistic effects of the nanostructure, materials, and energy storage mechanism result in the high capacitance [2615.32 F g−1 (6.76 F cm−2)] and excellent rate performance of the as-prepared electrode. This in situ growth system also provides a novel design concept to obtain effective, environmental friendly, and inexpensive composite materials for high-performance energy storage devices.