Mesoporous ZnCo₂O₄ nanosheet arrays are uniformly grown on Ni foam via a facile two-step method and directly use it as an integrated electrode for supercapacitors. The ZnCo₂O₄ nanosheet arrays/Ni foam electrode exhibits ultrahigh capacitance even with high current densities and excellent cycling stability after long term tests because of its unique nanostructure.