超级电容器
电容
比表面积
材料科学
化学工程
多孔性
生物炭
碳纤维
高分辨率透射电子显微镜
纳米技术
化学
透射电子显微镜
复合材料
热解
电极
复合数
有机化学
工程类
物理化学
催化作用
作者
Yanlei Zhang,Shiying Li,Zhishu Tang,Zhong-Xing Song,Jing Sun
标识
DOI:10.1016/j.diamond.2018.11.013
摘要
Here in this report, Xanthoceras sorbifolia seed coats are selected to prepare porous carbons. Biochar is first prepared by dry distillation of the seed coats, and then is transformed into porous carbon by KOH activation. The regulation of activation temperatures and ratios of activator is studied. The optimized condition is activation temperature of 750 °C, and the ratio of biochar to activator is 1:3. HRTEM, X-ray diffraction and the Brunauer-Emmett-Teller methods were used to characterize the samples. The porous carbon prepared under the optimum condition has a specific surface area of 2148 m2 g−1 with a large amount of micropores of about 0.5 nm–2 nm closely and orderly distributed, together with a certain number of mesporous (~12% of the total specific surface area), such a unique structure provides both a large storage space for electrons and a channel for them to passage quickly. Due to this unique architecture, the specific capacitance of the porous carbon is as high as 421 F/g at a current density of 0.5 A/g, with a moderate rate capability (259 F/g at 10 A/g), and good cycle stability (90.7% capacitance retention after 5000 cycles at 10 A/g), suggesting it one of the ideal materials for the development of supercapacitors. Symmetrical supercapacitor based on this material has also been assembled and tested to further verify the actual capacitance properties. The specific capacitance of the symmetrical supercapacitor is 276 F/g at 0.5 A/g, and 50 F/g was achieved when the current density was raised up to 10 A/g. Under the current density of 10 A/g, the capacitance only decreased slightly after the circulation of 5000 cycles, and the retention rate reached 86%, illustrates the practical application potential of this material.
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