超级电容器
材料科学
化学工程
比表面积
碳纤维
电容
介孔材料
电极
多孔性
无定形碳
纳米技术
无定形固体
化学
复合材料
催化作用
有机化学
复合数
物理化学
工程类
作者
Nannan Guo,Anjie Liu,Wanxia Luo,Rui Ma,Lihua Yan,Lili Ai,Mengjiao Xu,Luxiang Wang,Dianzeng Jia
标识
DOI:10.1016/j.jcis.2023.02.067
摘要
Coal-derived porous carbon with a large specific surface area is a common electrode material for supercapacitors. Its deep and branched micropores, dense bulk morphology and amorphous structure have greatly limited its practical applications. Herein, hybrid carbon materials were obtained from coal through oxidation followed by activation. The method allows tuning the morphology, porosity, structure, and the degree of graphitization. The pre-oxidation with KMnO4 can break raw coal into small hydrocarbon fragments, which deposit and grow on the surface of generated MnO during pyrolysis leading to hybrid carbon with mesoporous and graphitic nanostructures. Meanwhile, homogeneous etching of the carbon skeleton by the reaction intermediate of K2CO3 led to the formation of abundant active sites. Hence, the optimized sample exhibited a high capacitance of 333 F g−1 at 1 A g−1, an excellent rate capability with 58% capacitance retention at 100 A g−1 and superior cycle durability in a three-electrode system. Besides, an assembled symmetric two-electrode device displayed a high energy density of 8.9 Wh·kg−1 at 250 W·kg−1. This work proposed a facile and rational synthesis strategy by balancing the tradeoff between active sites and intrinsic conductivity and thus provided a new avenue for the value-added utilization of coal.
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