Three-dimensional networked NiCo2O4/MnO2 branched nanowire heterostructure arrays on nickel foam with enhanced supercapacitor performance

Abstract

Networked branched nanowire heterostructure (BNH) hybrid materials are very promising for supercapacitor electrodes, providing enhanced electrochemical performance compared with electrodes comprising a single constituent or core/shell nanowire heterostructures. Herein, by using a one-step hydrothermal reaction followed by a post-annealing treatment, we synthesized networked NiCo₂O₄/MnO₂ BNH arrays on Ni foam substrates and applied them as electrodes in supercapacitors. The as-prepared electrodes exhibit ultrahigh specific capacitance, excellent rate capability, and superb cycling stability at a high charge/discharge current density. This outstanding overall electrochemical performance is attributed to the effective conductive transport path between component materials, reduced electron- and ion-transport pathways, enhanced surface area, and facile electrolyte infiltration into the 3D networked BNH. The networked BNH design may provide a universal approach for the development of new electrode materials for high-performance pseudocapacitors.