Monodisperse carbon microspheres derived from potato starch for asymmetric supercapacitors

• Published in: Electrochimica acta Vol. 167; pp. 303 - 310
• Main Authors: Ruibin, Qiang, Zhongai, Hu, Yuying, Yang, Zhimin, Li, Ning, An, Xiaoying, Ren, Haixiong, Hu, Hongying, Wu
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 10.06.2015
• Subjects: Asymmetric supercapacitor; Carbon microspheres; hydrothermal process; Potato starch; Supercapacitive performances; Supercapacitive performances; Asymmetric supercapacitor; hydrothermal process; Potato starch; Carbon microspheres
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2015.03.190

[Display omitted] Uniform and monodisperse carbon microspheres (MCMSs) are synthesized via a catalyst-free and hydrothermal process by following a high temperature carbonization, in which potato starch is used as raw material. The morphology and microstructure of the as-obtained samples are characterized using SEM, TEM, XRD, Raman, FTIR and BET. TEM image shows that the products consist of carbon microspheres with a mean diameter of about 250nm. BET specific surface area of MCMSs is up to 456m2·g−1. Furthermore, the supercapacitive performances of the MCMSs are investigated by cyclic voltammogram (CV), galvanostatic charge-discharge, and electrochemical impedance spectroscopy (EIS). The experimental results indicate that the MCMSs exhibits not only high specific capacitance of 245F·g−1 and good rate capability (the specific capacitance at 10A·g−1 is 61% of that at 1A·g−1), but also excellent cycle stability (no obvious capacitance decay after 4,000 cycles at 3A·g−1). An asymmetric electrochemical capacitor is assembled by using the obtained MCMSs as negative electrode and reduced graphene oxide (RGO) as positive electrode. The as-assembled MCMSs//RGO capacitor can cycle reversibly in a voltage of 0–1.5V and give a high energy density of 21.5Wh·kg−1 at a power density of 759W·kg−1.