In this work, the asymmetric supercapacitor in which spherical porous VN is used as a negative electrode and NiO x as a positive electrode was assembled in 1M KOH aqueous electrolyte. The spherical porous VN negative material has a specific capacitance of 580F/g and the NiO x positive electrode a specific capacitance of 680F/g. The VN/NiO x symmetric supercapacitor shows a sloping voltage profile from 0.5 to 1.45V with excellent reversibility and delivers a specific capacitance of 139F/g and an energy density of 63Wh/kg based on the total weight of the active electrode materials. The VN/NiO x asymmetric supercapacitor shows a good cycling behavior, about 15% specific capacitance decay after 1000 cycles. It also exhibits an excellent rate capability, even at a power density of 2400W/kg, it has a specific energy 26Wh/kg compared with 50Wh/kg at the power density about 365W/kg.