Coal Tar Pitch-Based Porous Carbon Loaded MoS2 and Its Application in Supercapacitors.

In this paper, with coal tar pitch as the carbon source, porous carbon (PC) was prepared by one-step carbonization. To improve the energy density of coal tar pitch-based porous carbon, MoS2@PC was prepared by a hydrothermal method on a PC substrate. The effect of MoS2 loading on the structure and electrochemical properties of the sample was studied. The results show that the specific surface area of the MoS2@PC-0.3 synthesized is 3053 m2 g-1, and the large specific surface area provides sufficient attachment sites for the storage of electrolyte ions. In the three-electrode system, the specific capacitance of MoS2@PC-0.3 at 0.5 A g-1 is 422.5 F g-1, and the magnification performance is 57.3% at 20 A g-1. After 10,000 charge/discharge cycles, the capacitance retention rate of the sample is 76.73%, with the Coulombic efficiency being 100%. In the two-electrode test system, the specific capacitance of MoS2@PC-0.3 at 0.5 A g-1 is 321.4 F g-1, with the power density and energy density being 500 W kg-1 and 44.6 Wh kg-1, respectively. At a current density of 20 A g-1, the capacitance retention rate is 87.69% after 10,000 cycles. This study greatly improves the energy density of PC as the electrode material of supercapacitors.

N/O Co-doped Porous Carbons Derived from Coal Tar Pitch for Ultra-high Specific Capacitance Supercapacitors.

In this paper, a series of N/O co-doped porous carbons (PCs) were designed and used to prepare coal tar pitch-based supercapacitors (SCs). The introduction of N/O species under the intervention of urea effectively improves the pseudocapacitance of PCs. The results show that the specific surface area of synthesized N3PC4-700 is 1914 m2 g-1, while the N and O contents are 1.3 and 7.2%, respectively. The unique interconnected pore structure and proper organic N/O co-doping, especially the introduction of pyridine-N and pyrrole-N, are beneficial for improving the electrochemical performance of PCs. In the three-electrode system, the specific capacitance and rate capability of N3PC4-700 are 532.5 F g-1 and 72.5% at the current densities of 0.5 and 20 A g-1, respectively. In addition, the specific capacitance of N3PC4-700 in a coin-type symmetric device is 315.5 F g-1 at 0.5 A g-1. The N3PC4-700 electrode provides an energy density of 43.8 W h kg-1 with a power density of 0.5 kW kg-1 and still maintains a value of 29.7 at 10 kW kg-1. After 10,000 charge/discharge cycles, the retention rate was as high as 96.7%. In order to obtain high-performance carbon-based SCs, the effective identification and regulation of organic N/O species is necessary.