Preparation and electrochemical properties of low-temperature activated porous carbon from coal tar pitch

Using coal tar pitch (CTP) as a carbon source and KOH as an activator, the one-step carbonization activation method was used to explore the effects of different activation temperatures on the development of the hierar-chical porosity of carbon and its performance as electrodes in a supercapacitor. The results show that the specific surface area and pore volume of the prepared carbon material ACTP-3-600 at the activation temperature of 600 degrees C are higher than those at other temperatures, and the micropores account for about 90.5 %. When the mass ratio of KOH to CTP is 3, the specific capacitance of ACTP-3-600 can reach 475 F g-1 at a current density of 0.5 A g-1. Under the condition of a high current density of 10 A g-1, its specific capacitance can still maintain 301.8 F g-1, and the rate performance is 63.5 %. The symmetric supercapacitor assembled with it can achieve an energy density of 20.2 Wh kg- 1 (at a power density of 450.0 W kg -1) in 1 M Na2SO4 electrolyte. After 10,000 cycles, the prepared carbon material has a capacitance retention rate of 91.2 % and good cycle stability. Because the activation temperature is relatively low, the method is simple, and the yield of prepared carbon material can reach 52.4 %, which is much higher than that of biomass (about 20 %). The prepared method can greatly reduce the cost of carbon materials. It is a feasible and helpful route to prepare high-performance hierarchical porous carbon materials.

Automated summary

Using coal tar pitch (CTP) and KOH as carbon source and activator respectively, the study investigates the effects of different activation temperatures on the hierarchy and performance of carbon electrodes in supercapacitors. The results demonstrate that ACTP-3-600 activated at 600 degrees C shows higher specific surface area, pore volume, and superior performance compared to other temperatures. The symmetric supercapacitor assembled with it achieves an energy density of 20.2 Wh kg-1 (at a power density of 450.0 W kg -1) in 1 M Na2SO4 electrolyte, with a capacitance retention rate of 91.2 % after 10,000 cycles. The prepared method offers a simple and cost-effective approach to high-performance hierarchical porous carbon materials.