The relationship between the high-frequency performance of supercapacitors and the type of doped nitrogen in the carbon electrode

氮掺杂构型对超级电容器高频响应的影响机制

Nitrogen doping has been widely used to improve the performance of carbon electrodes in supercapacitors,particularly in terms of their high-frequency response.However,the charge storage and electrolyte ion response mechanisms of different nitrogen dopants at high frequencies are still unclear.In this study,melamine foam carbons with different configurations of surfacedoped N were formed by gradient carbonization,and the effects of the configurations on the high-frequency response behavior of the supercapacitors were analyzed.Using a combination of experiments and first-principle calculations,we found that pyrrolic N,characterized by a higher adsorption energy,increases the charge storage capacity of the electrode at high frequencies.On the other hand,graphitic N,with a lower adsorption energy,increases the speed of ion response.We propose the use of adsorption energy as a practical descriptor for electrode/electrolyte design in high-frequency applications,offering a more universal approach for improving the performance of N-doped carbon materials in supercapacitors.

氮掺杂炭材料已被广泛用于增强超级电容器的高频响应能力。然而,不同氮构型在高频下的电荷存储和离子响应机制仍不清楚。本研究通过梯度炭化构筑了具有不同表面N掺杂构型的三聚氰胺泡沫炭,并以此为模型材料全面分析了N掺杂构型对超级电容器高频响应行为的影响。结合实验结果和第一性原理计算,发现具有较高吸附能的吡咯氮可以增强高频下炭电极的电荷存储能力。而具有较低吸附能的石墨氮则有助于离子在高频下的快速响应。此外,提出吸附能可作为高频下电极/电解液界面设计的描述符,这为优化氮掺杂炭材料的高频性能提供了更普适的方法。这些结果为开发用于高频超级电容器的氮掺杂炭电极材料提供了指导。