煤焦油衍生模板碳孔隙重整及高体积电容性能

Among all kinds of energy storage devices,supercapacitors have attracted wide attention because of outstanding characteristics such as high power density, ultra-fast charge and discharge speed, and long cycle life. Porous carbon materials are widely used in electrical doubl layer capacitor (EDLC) electrode materials because of their adjustable multi-scale structure, high specific surface area and abundant pore structure. However, the high porosity results in loose carbon skeleton structures, which reduces the material density and further limits the volumetric performance of the double-layer capacitor. Therefore, the key to enhance the volumetric performance of double-layer capacitors lies in carbon electrode materials with a rational pore structure and a dense skeleton. In this study, low-cost coal tar was utilized as the carbon source, and a template method was used to carbonize the different template materials prepared by the phase transformation process after coated by tar, resulting in carbon nanosheets (PCS) with dense porous structure. The optimized hierarchical pore structure in the material reduced the proportion of surplus meso-/ macropores, resulting in a high packing density of 0.64 g/ cm³ and enabling both excellent gravimetric and volumetric capacitance properties. With an aqueous EDLC as demonstration, the fabricated PCS electrode can achieve a high-level volumetric capacitance of 277 F/ cm³ at a low mass loading of 2 mg/ cm² and 243 F/ cm³ at a high mass loading of 8 mg/ cm², with maximum volumetric energy density and power density reaching 8.46 Wh/ L and 10.9 kW/ L, respectively. In addition, double-layer symmetric capacitors also exhibited excellent cyclic stability, demonstrating the potential of PCS in high-density energy storage in double-layer capacitors.