In this paper, a simple “one-step” route is introduced to prepare a kind of novel honeycomb-like hierarchical porous carbon (h-HPC) by carbonizing and activating garlic seeds. Due to its special microstructure, h-HPC shows excellent electrochemical properties and high supercapacitor performances. The experimental results reveal the following: (1) There exists an optimal condition for synthesizing h-HPC, i.e., 700 °C carbonization temperature and 1:1 mass ratio of KOH and garlic seeds. (2) h-HPC has a three-dimensional interconnected porous structure and exhibits a specific surface area as high as 1417 m²/g with a narrow pore size distribution. (3) When h-HPC is employed as an electrode material in supercapacitors, its specific capacitance reaches a value up to 268 F/g at a current density of 0.5 A/g and excellent rate capability. (4) The h-HPC-based symmetric supercapacitor shows a high energy density of 31.7 Wh/kg at a power density of 500 W/kg and retains 99.2% of the initial capacitance after 10,000 charge/discharge cycles at 200 mV/s. When compared with similar works, these data are competitive, which demonstrates that the garlic-derived h-HPC is a kind of promising electrode material for the next-generation high-energy-density supercapacitors.

中文翻译：

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蜂窝状分层多孔碳大蒜种子的“一步式”碳化活化及其高超级电容器性能

本文介绍了一种简单的“一步一步”路线，通过碳化和活化大蒜种子来制备一种新型的蜂窝状分层多孔碳（h-HPC）。由于其特殊的微观结构，h-HPC具有出色的电化学性能和较高的超级电容器性能。实验结果表明：（1）存在合成h-HPC的最佳条件，即700℃的碳化温度和KOH与大蒜种子的质量比为1：1。（2）h-HPC具有三维互连多孔结构，比表面积高达1417 m ²/ g，孔径分布窄。（3）当将h-HPC用作超级电容器的电极材料时，其比电容在0.5 A / g的电流密度下具有高达268 F / g的值，并且具有出色的倍率性能。（4）基于h-HPC的对称超级电容器在500 W / kg的功率密度下显示31.7 Wh / kg的高能量密度，并在200 mV / s的10,000次充电/放电循环后保留了99.2％的初始电容。当与类似作品进行比较时，这些数据具有竞争性，这表明大蒜衍生的h-HPC是下一代高能量密度超级电容器的一种有希望的电极材料。