We report here that poly-o-phenylenediamine as a solid carbon source can be facilely carbonized to produce three-dimensional nitrogen-doped graphene (3DNGN) with the aid of Ni(NO3)(2) powder. In situ formed Ni nano particles by deconiposition of Ni(NO3)(2) serve as both template and catalyst for the formation of 3DNGN. The 3DNGN with interconnected porous structure and high content of nitrogen doping can ensure large electrolyte -accessible surface area, rapid ion transportation, and fast electron transport, resulting in high electrochemical performance. The 3DNGN shows a high specific capacitance of 312 F g(-1) at 1 A g(-1), with good capacitance retention capability and good cycling stability, and outputs a high average energy power density of 10.8 W h kg(-1) and a high maximum power density of 595 kW kg(-1) in aqueous KOH electrolyte. Due to the great pseudocapacitance in aqueous H2SO4 electrolyte, the specific capacitance of the 3DNGN can reach a high value of 345 F g(-1) at 1 A g(-1). (C) 2017 Elsevier B.V. All rights reserved.