In this work, we report on the use of hydrothermal and hydrogenation processes to synthesize oxygen-deficient NiMoO4 nanoflake arrays (OD-NF) and nanowire arrays (OD-NW) for electrode applications. The introduction of oxygen vacancies into NiMoO4 increased the interlayer spacing of the crystal structure and Mo6+ in NiMoO4 was partially reduced to Mo4+. In addition to increasing the conductivity, the oxygen vacancies also promoted charge storage kinetics, while retaining the crystal structure of NiMoO4. The oxygen vacancies considerably influenced the capacitive performance of NiMoO4. Notably, OD-NF showed better electrochemical performance than that of OD-NW. Furthermore, our asymmetric supercapacitor device composed of NiMoO4 OD-NF and active carbon achieved 49.1 Wh kg(-1) at a power density of 800Wkg(-1) and retained a remarkable 94.2% specific capacitance after 6000 cycles.