Three-dimensional polyaniline nanowire arrays are vertically grown on free-standing acidized carbon nanotube paper, and further carbonized to nitrogen doped carbon for supercapacitor electrodes. The three-dimensional porous structure of the as-prepared nitrogen doped carbon can increase the specific surface area and benefit ion transport into the interior of the electrode materials. Nitrogen doping can effectively improve the wettability of the carbon surface in the electrolyte and enhance the specific capacitance by a pseudocapacitive effect. Thus, free-standing nitrogen doped carbon nanowires on conductive carbon nanotube paper show excellent electrochemical performance as a supercapacitor electrode material. At a current density of 2 A g(-1), the specific capacitance reaches 210 F g(-1) with 94% capacitance retention after 10,000 cycles. (C) 2016 Elsevier B.V. All rights reserved.