Abstract
Enhancing the performance of porous carbon materials has become a key focus in current research. In this study, oxygen-containing functional groups were introduced into the carbon skeleton to improve its properties. Air preoxidation can not only introduce oxygen-containing functional groups, but also pretreat coal tar pitch by removing light aromatic components to form a cross-linking network to improve its pore structure. It also helps KOH impregnation to achieve uniform contact with the carbon source, thereby obtaining a uniform pore structure. The optimized material OPC-600 was successfully synthesized. In contrast to preoxidation methods using strong oxidants such as H(2)O(2) or HNO(3), which involve safety risks and environmental concerns, the air preoxidation approach is green and straightforward. OPC-600 exhibits a high specific surface area of 2227.93 m(2)/g and a specific capacitance of 273 F/g at 0.5 A/g. It also demonstrates excellent cycling stability, retaining 95.69% of its capacitance after 10,000 cycles at 5 A/g. The uniform pore structure achieved through KOH impregnation outperformed the carbon material prepared by Yang et al., which showed 93.3% retention under similar cycling conditions. Furthermore, when assembled into a coin cell, the device delivered an energy density of 32.95 Wh/kg at a current density of 1 A/g, surpassing most carbon-based materials reported in the literature. The air preoxidation combined with KOH impregnation produced a porous carbon material with not only a high specific surface area but also a dominant microporous structure, providing abundant sites for efficient charge storage. As a result, OPC-600 exhibits outstanding electrochemical performance. This study provides a novel and efficient strategy for the utilization of coal tar pitch and offers new insights into the design of advanced carbon-based supercapacitors.