Heteroatom-doped porous carbons with optimized pore structure have become attractive as supercapacitor electrodes. In this work, hierarchical porous carbon possessing optimized mesopore structure and nitrogen doping (NHPC) was prepared by carbonizing the mixtures of potassium humate and manganous nitrate (Mn(NO₃)₂). The NHPC exhibits similar specific surface area, while significantly higher mesopore ratio with narrow pore size distribution compared with hierarchical porous carbon without the Mn(NO₃)₂ (HPC), which benefit ion storage and transfer in the corresponding electrodes. Moreover, the NHPC shows higher nitrogen content of (3.89 at.%) than HPC (1.99 at.%), leading to enhanced wettability and pseudo-capacitance effect. Based on these optimized characteristics, even with an ultrahigh mass loading of 13.56 mg cm⁻², NHPC demonstrates improved gravimetric capacitance of 258 F g⁻¹ and areal capacitance of 23.1 μF cm⁻² at 0.046 A g⁻¹ (18.9% and 12.1% higher than HPC, respectively), as well as significantly enhanced rate capability. Moreover, NHPC exhibits excellent cycling stability with 93.6% capacitance retention after 10,000 cycles at a current density of 2.32 A g⁻¹. This work provides a facile and low-cost strategy for preparing the nitrogen-doped hierarchical porous carbon for practical supercapacitor application.

具有优化的孔结构的掺杂杂原子的多孔碳已成为超级电容器电极的吸引力。在这项工作中，通过碳化腐植酸钾和硝酸锰（Mn（NO ₃）₂）的混合物，制备了具有优化的中孔结构和氮掺杂（NHPC）的分级多孔碳。与没有Mn（NO ₃）_2的分层多孔碳相比，NHPC具有相似的比表面积，同时具有显着更高的中孔比和窄的孔径分布（HPC），有利于离子在相应电极中的存储和转移。此外，NHPC的氮含量（3.89 at。％）比HPC（1.99 at。％）高，从而提高了润湿性和拟电容效果。基于这些优化的特性，即使在13.56 mg cm ^-2的超高质量负载下，NHPC在0.046 A g ^-1（18.9％和12.1）时也显示出258 F g ^-1的重量分析电容和23.1μFcm ^-2的面积电容得到了改进。分别比HPC高％）和显着增强的速率功能。此外，NHPC表现出出色的循环稳定性，在电流密度为2.32 A g ^{-1的条件下，}经过10,000次循环后，电容保持率为93.6％。。这项工作为制备用于实际超级电容器应用的氮掺杂分级多孔碳提供了一种简便且低成本的策略。