Construction of unique Co3O4@CoMoO4 core/shell nanowire arrays on Ni foam by the action exchange method for high-performance supercapacitors

Abstract

In this work, hierarchical Co₃O₄@CoMoO₄ core/shell nanowire arrays on nickel foam are fabricated by a facile hydrothermal ion exchange method. The Co₃O₄ nanowires are fully covered by ultrathin mesoporous CoMoO₄ nanosheets. A possible growth mechanism for the CoMoO₄ involves the capturing of the part of the cobalt ions of the Co₃O₄ nanowires by the molybdenum acid radical without annealing. When investigated as binder-free electrodes for supercapacitors (SCs), such unique Co₃O₄@CoMoO₄ core/shell hybrid electrodes exhibited ultrahigh areal capacitances, which are several times larger than the pristine Co₃O₄ electrode. The electrode exhibits a high specific capacitance of 1040 F g⁻¹ at a current density of 1 A g⁻¹ and an excellent cycling stability (5000 cycles). The remarkable electrochemical performance is attributed to the rational combination of two electroactive materials and the array configuration.