Xanthoceras sorbifolia seed coats derived porous carbon with unique architecture for high rate performance supercapacitors

• Published in: Diamond and related materials 2019-01, Vol.91, p.119-126
• Main Authors: Zhang, Yan-Lei, Li, Shi-Ying, Tang, Zhi-Shu, Song, Zhong-xing, Sun, Jing
• Format: Article
• Language: English
• Subjects: Activation; Architecture; Biomass derived; Biomaterials; Capacitance; Carbon; Carbon materials; Current density; Distillation; Electrochemical properties; Porous materials; Specific surface; Supercapacitors; Surface area; X-ray diffraction
• ISSN: 0925-9635; 1879-0062
• DOI: 10.1016/j.diamond.2018.11.013

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. [Display omitted] •Biomass waste is transformed into high value added porous carbon materials.•The porous carbon structure can be simply tuned by temperature and activator regulation.•The prepared porous carbon material has a unique microporous structure.•The prepared porous carbon material exhibited high rate performance for supercapacitors.