Heteroatoms in situ-doped hierarchical porous hollow-activated carbons (HPHACs) have been prepared innovatively by pyrolyzation of setaria viridis combined with alkaline activation for the first time. The micro-morphology, pore structure, chemical compositions, and electrochemical properties are researched in detail. The obtained HPHACs are served as outstanding electrode materials in electrochemical energy storage ascribe to the particular hierarchical porous and hollow structure, and the precursor setaria viridis is advantage of eco-friendly as well as cost-effective. Electrochemical measurement results of the HPHACs electrodes exhibit not only high specific capacitance of 350 F g⁻¹ at 0.2 A g⁻¹, and impressive surface specific capacitance (C_s) of 49.9 μF cm⁻², but also substantial rate capability of 68% retention (238 F g⁻¹ at 10 A g⁻¹) and good cycle stability with 99% retention over 5000 cycles at 5 A g⁻¹ in 6 M KOH. Besides, the symmetrical supercapacitor device based on the HPHACs electrodes exhibits excellent energy density of 49.5 Wh kg⁻¹ at power density of 175 W kg⁻¹, but still maintains favorable energy density of 32.0 Wh kg⁻¹ at current density of 1 A g⁻¹ in 1-ethy-3-methylimidazolium tetrafluoroborate (EMIMBF₄) ionic liquid electrolyte, and the excellent cycle stability behaviour shows the nearly 97% ratio capacitance retention of the initial capacitance after 10,000 cycles at current density of 2 A g⁻¹. Overall, the results indicate that HPHACs derived from setaria viridis have appealing electrochemical performances thus are promising electrode materials for supercapacitor devices and large-scale applications.

中文翻译：

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用于高性能超级电容器的杂原子原位掺杂分级多孔中空活性炭

原位掺杂的分级多孔空心活性炭（HPHACs）是杂化了的，首先通过氧化狗尾草热解并结合碱活化来制备。详细研究了微观形貌，孔结构，化学成分和电化学性能。所获得的HPHACs被用作电化学能量存储中的杰出电极材料，归因于特定的分层多孔和中空结构，并且前体狗尾草绿色环保且具有成本优势。HPHACs电极的电化学测量结果不仅显示出在0.2 A g ^-1下具有350 F g ^-1的高比电容，而且还具有令人印象深刻的表面比电容（C _s）49.9μF厘米^-2，但68％的保持率（238 F G也显着速率能力^-1以10 A G ^-1）中并在5甲克用99％的保留良好的循环稳定性超过5000个循环^-1在6M啊 此外，基于HPHACs电极的对称超级电容器器件在175 W kg ^-1的功率密度下表现出49.5 Wh kg ^-1的出色能量密度，但在1 A g的电流密度下仍保持32.0 Wh kg ^-1的有利能量密度。^-1-乙基-3-甲基咪唑鎓四氟硼酸酯中的^-1（EMIMBF ₄）离子液体电解质，优异的循环稳定性能表明在2 A g ^-1的电流密度下进行10,000次循环后，初始电容的电容保持率接近97％。总体而言，结果表明，源自狗尾草的HPHAC具有吸引人的电化学性能，因此是用于超级电容器设备和大规模应用的有前途的电极材料。