Boron and nitrogen co-doped porous carbon for supercapacitors: A comparison between a microwave-assisted and a conventional hydrothermal process. (December 2020)

• Record Type: Journal Article
• Authors: Zhou, Yalan; Yan, Wen; Yu, Xiya; Chen, Tingting; Wang, Shirui; Zhao, Weigang
• Is Part Of: Journal of energy storage. Volume 32(2020)
• Publication Date: 2020-12
• Subjects: Microwave-assisted hydrothermal -- Conventional hydrothermal -- Heteroatoms doped -- Porous carbon; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2020.101706
• Languages: English
• ISSNs: 2352-152X

Abstract

Highlights: Cost-effective porous carbons from sword bean shells were synthesized. N and B heteroatoms have been successfully incorporated into the porous carbon. MHT method is much better for supercapacitor due to the superior pore structures. Abstract: An ultrafast synthesis method is proposed for a boron and nitrogen co-doped porous carbon using biomass material as a precursor through a combination of a microwave-assisted hydrothermal method (MHT) followed by a pyrolysis process. Compared with a conventional hydrothermal carbonization method (HTC), the MHT method exhibits unparalleled advantages, such as a high energy efficiency and a uniform and ultrafast reaction. The pore structure, elemental composition and electrochemical performance of the materials from the two methods were studied and compared. The results showed that when water was used as the solvent, a porous texture with a surface area of 823 m 2 g −1 was obtained by the HTC after 24 h; in contrast, a similar surface area of 813 m 2 g −1 could be easily obtained in only 20 min with MHT. Furthermore, when boric acid was used as the solvent, MHT-20min-10% presented similar heteroatom (B and N) contents as the HTC sample but with a significantly improved surface area (994 vs. 666 m 2 g −1 ) and specific capacitance (120 vs. 106 F g −1 ) compared to those of HTC-24h-10%. Therefore, compared with the HTC, MHT is an ultrafast synthesis method and also is the best option to obtain high surface area porous carbon materials doped with B and N heteroatoms with suitable pore size distribution, which are beneficial in electrode materials for supercapacitors.