Three-dimensional Co₃O₄@NiMoO₄ core/shell nanowire arrays on Ni foam for electrochemical energy storage.

In this work, we report a facile two-step hydrothermal method to synthesize the unique three-dimensional Co3O4@NiMoO4 core/shell nanowire arrays (NWAs) on Ni foam for the first time. The Co3O4 nanowires are fully covered by ultrathin mesoporous NiMoO4 nanosheets. When evaluated as a binder-free electrode for supercapacitors in a 2 M KOH aqueous solution, the Co3O4@NiMoO4 hybrid electrode exhibits a greatly enhanced areal capacitance of 5.69 F cm(-2) at a high current density of 30 mA cm(-2), nearly 5 times that of the pristine Co3O4 electrode (1.10 F cm(-2)). The energy density of the hybrid electrode is 56.9 W h kg(-1) at a high power density of 5000 W kg(-1). In addition, the Co3O4@NiMoO4 hybrid electrode also exhibits good rate capability and cycling stability, which would hold great promise for electrochemical energy storage.