Supercapacitors and Li-ion batteries are two types of electrical energy storage devices. To satisfy the increasing demand for high-performance energy storage devices, traditional electrode materials, such as transition metal oxides, conducting polymers and carbon-based materials, have been widely explored. However, the results obtained to date remain unsatisfactory, and the development of inexpensive electrode materials (especially for commercial manufacturing) with superior electrochemical performance for use in supercapacitors and in Li-ion batteries is still needed. The as-prepared NiMoO4 nanosheets (NSs) with interconnecting nanoscale pore channels and an ultrathin structure provide a large electrochemical active area, which facilitates electrolyte immersion and ion transport and provides effective pathways for electron transport. Therefore, the as-prepared NiMoO4 NS electrode exhibits a high specific capacity and an excellent rate capability and cycling stability in supercapacitors and in Li-ion batteries. Moreover, a high energy density (43.5 W h kg-1 at 500 W kg-1) was obtained for the symmetric supercapacitor (SSC) composed of two sections of NiMoO4 NSs.