A facile one-pot process for synergistic conversion of coal char and methane is conducted by employing K2CO3 as the catalyst. Besides syngas production, valuable carbon products are obtained and used to serve for supercapacitor electrodes. Effect of the operating parameters (including the catalyst dosage, gas feed flow rate, reaction temperature and time) is evaluated on electrochemical performance of the as-prepared carbon. The appropriate surface and structural properties enable the prepared carbon electrode to have a remarkable capacitive performance, along with a specific capacitance up to 125 F/g at a scan rate of 5 mV/s and 133 F/g at a current density of 1 A/g. According to the potential capacitive contribution of the carbon species, the high capacitive performance is mainly attributed to formation and growth of abundant carbon fibers in the one-pot process. (C) 2019 Elsevier Inc. All rights reserved.