A hydrothermal carbonization process for the preparation of activated carbons from hemp straw : an efficient electrode material for supercapacitor application

• Main Authors: Jiang, Xia, Shi, Gaofeng, Wang, Guoying, Mishra, Puranjan, Liu, Chao, Dong, Yucan, Zhang, Peng, Tian, Haoqi, Liu, Yanrong, Wang, Zhao, Zhang, Qi, Zhang, Hongquan
• Format: Article
• Language: English
• Published: Institute for Ionics 2019
• Subjects: QD Chemistry; TP Chemical technology
• Online Access: http://umpir.ump.edu.my/id/eprint/25385/1/A%20hydrothermal%20carbonization%20process%20for%20the%20preparation%20.pdf; http://umpir.ump.edu.my/id/eprint/25385/; https://doi.org/10.1007/s11581-019-02850-8; https://doi.org/10.1007/s11581-019-02850-8

In the present study, a hemp straw activated carbon (HSAC) was simply prepared by hydrothermal process followed by a pre-oxidization and carbonization by KOH solid-state activation. The as-synthesized HSAC shows abundant porosity, which is designed to be beneficial to the fast transportation of electrolyte. The preparation conditions for HSACs under different mass ratios of KOH:precursors were optimized, and the sample obtained by a mass ratio of 4:1 showed an outstanding capacitive property (specific capacitance of 279 F g−1at 0.5 A g−1 current density). Besides, the capacitance of 91.6% was retained after 5000 charge-discharge cycles under 2 A g−1 current density. The resulting symmetrical supercapacitor obtained by using the HSAC electrodes exhibited an excellent electrochemical performance, which successfully illuminated a LED light. The HSAC has great potentials as electrode material for high-performance supercapacitor, which opens a new way for value increment of natural products.