Fabricating cost effective and high-performance electrodes is essential to the development of vanadium flow battery (VFB). Moreover, improving the stability of electrodes in acidic electrolyte remains key issues. In this work, we describe a simple method to prepare novel electrodes composed of N-doped carbon nanospheres (NCS) grown on graphite felt (GF) fibers. Dopamine monomers are used as both carbon and nitrogen source. Physical and electrochemical results reveal that the as-prepared NCS/GF electrode exhibits excellent electrocatalytic activity as well as wettability for vanadium ion redox reactions. The single cell tests at current densities of 50–300mAcm−2 demonstrate superior battery performance in terms of energy efficiency and capacity retention. Exceptional durability of the NCS catalyst is confirmed by long-term cycles at a higher current density of 150mAcm−2. NCS/GF electrode also shows excellent temperature adaptability from −15°C to 50°C. The facile approach reported in this study can pave a new route to fabricate high-performance electrodes for VFB.