Potassium citrate synergistically optimizes various nanostructures of wheat straw-derived carbon materials to enhance the electrochemical performance of supercapacitors
摘要
O-doped porous carbon materials were synthesized using wheat straw as the precursor and the activation strategy of potassium citrate. By regulating the mass of potassium citrate, the coordinated adjustment of various structural parameters in carbon materials can be achieved. The electrochemical detection results show that the WSC-1 synthesized by adding 1 g of potassium citrate has the highest electrochemical performance, which is attributed to the balance among various structural parameters in WSC-1. That is, WSC-1 does not have the largest surface area and the highest O atom content. The surface area, O atom content, graphitization degree and pore size distribution of WSC-1 are all at a moderate level. In the three-electrode system, when the current density is 1 A g−1, the mass-specific capacitance of WSC-1 is 199.7 F g−1. When the current density is 5 A g−1, the capacitance retention rate is 87.1%. The symmetrical supercapacitor (WSC-1//WSC-1) constructed in the two-electrode system has an energy density of 12.4 Wh kg−1 when the power density is 350 W kg−1. After 8000 cycles, its specific capacitance is 100% of the initial value. This work provides new ideas for the structural design of high-performance carbon materials.