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

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.