Metal nitride-based supercapacitors can provide superb electrical conductivity, high capacitance, and wide operating potential window, but they do not have sufficient fabrication strategy to construct advanced nano-structure beneficial to electrochemical process. In this paper, we report an in-situ preparation approach of vanadium nitride nanoparticles on porous carbon nanospheres (PCNS@VNNP) by the ammonification process of ionic amphiphilic triblock copolymer micelles/vanadium-contained ions system in NH3/N-2 atmosphere. The prepared PCNS@VNNP material has a wide operating potential of 1.2 V, and a capacitance of 229.7 F/g (275.6C/g). A hybrid supercapacitor device of PCNS@VNNP//NiO exhibits a high energy density of 16 Wh/kg at the power density of 800 W/kg. The improvement mostly stems from the quantum dot size of vanadium nitride and the supporting of porous carbon, which would dramatically enhance the utilization of active material without affecting its electric conductivity. (C) 2016 Elsevier Ltd. All rights reserved.