Three-dimensional (3D) carbon-coated NiCo2S4 nanowires structures doped with nitrogen are used for energy storage and conversions. The nitrogen doping in both the carbon layer and NiCo2S4 nanowires enhances the electrochemical performances. Here, an easily scalable and simple temperature treatment has been used to decorate carbon-coated NiCo2S4 nanowires with nitrogen doping (N-C@NiCo2S4 NWs) in 3D carbon architecture (carbon cloth). Benefiting from the nitrogen doping and ultrathin carbon layer, the as-prepared 3D N-C@NiCo2S4 NWs electrode exhibits the superior electrochemical performance for both asymmetric supercapacitor and electrocatalytic water splitting. An asymmetric supercapacitor assembled by the N-C@NiCo2S4 NWs and active carbon electrodes achieves a high energy density of 1.72 mWh cm(-3) (68.87 Wh kg(-1)) under a power density of 10.63 mW cm(-3) (425 W kg(-1)) with 90.1% retention of initial capacitance after 10,000 cycles. When employed as the electrocatalyst, the N-C@NiCo2S4 NWs show high activities towards electrocatalytic water splitting. (C) 2019 Elsevier Inc. All rights reserved.