Improvement of a commercial activated carbon for organic electric double-layer capacitors using a consecutive doping method

In this study, a consecutive doping method was used to improve the electrochemical properties of a commercial activated carbon (YP50f) as an electrode material for organic electric double-layer capacitors (EDLCs). In the consecutive doping method, nitrogen doping is carried out after an oxygen-doping process. Using the consecutive doping method, we prepared a carbon material with both a large specific surface area and high electrical conductivity. The specific surface area of the carbon material was mainly developed during the oxygen-doping step, whereas electrical conductivity was enhanced in the nitrogen-doping step. On the basis of the properties of the consecutively doped carbon material, we expected the prepared carbon material to exhibit good electrochemical properties when used as electrode materials for organic EDLCs. From the results of electrochemical characterizations, we observed that the consecutively doped carbon material showed a highly improved capacitance compared to the YP50f under all of the applied charge–discharge rates. Consequently, we concluded that the consecutive doping method is an effective method to prepare carbon materials with good electrochemical properties as electrode materials for organic EDLCs as a result of both their enhanced specific surface area and their enhanced electrical conductivity.