A negative electrode material of nano vanadium nitride/interconnected porous carbon (Nano-VN/IPC) is fabricated via a novel method combining surface-initiated electrochemical mediated ATRP and heat-treatment process. The structural and composition characterization display that a low crystallinity of VN nanoparticles is obtained, which distributes uniformly in the interconnected pores of the carbon scaffold materials. The high-distribution of nano-VN particles in the interconnected pores significantly enhances the usage efficiency of the electrochemistry-active materials to ensure the high electrochemical performance of the electrode materials. The interconnected pore structure is convenient for diffusion and transfer of electrolyte ions during charging-discharging process. The Nano-VN/IPC electrodes exhibit a high specific capacitance of 284.0 F/g at 0.5 A/g in 2 M KOH aqueous electrolyte with a low resistance and good rate capability. In addition, an asymmetric supercapacitor is assembled with Ni(OH)(2) and Nano-VN/IPC electrodes as the positive and negative electrodes. The device presents a high specific capacitance of 122 F/g at the current density of 0.5 A/g, and when the current density increases to 5 A/g the capacitance still remains 70 F/g. Remarkably, the device delivers an ultrahigh power density of 35.6 Wh/kg at a power density of 362.5 W/kg. (c) 2017 Elsevier Ltd. All rights reserved.