Tungsten Oxideolypyrrole Core-Shell Nanowire Arrays as Novel Negative Electrodes for Asymmetric Supercapacitors

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 11; no. 6; pp. 749 - 755
• Main Authors: Wang, Fengmei, Zhan, Xueying, Cheng, Zhongzhou, Wang, Zhenxing, Wang, Qisheng, Xu, Kai, Safdar, Muhammad, He, Jun
• Format: Journal Article
• Language: English
• Published: 01.02.2015
• Subjects: Arrays; Asymmetry; Capacitance; Capacitors; Devices; Electrodes; Nanostructure; Nanowires; Supercapacitors; Tungsten
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201402340

Among active pseudocapacitive materials, polypyrrole (PPy) is a promising electrode material in electrochemical capacitors. PPy-based materials research has thus far focused on its electrochemical performance as a positive electrode rather than as a negative electrode for asymmetric supercapacitors (ASCs). Here high-performance electrochemical supercapacitors are designed with tungsten oxidePy (WO sub(3)Py) core-shell nanowire arrays and Co(OH) sub(2) nanowires grown on carbon fibers. The WO sub(3)Py core-shell nanowire electrode exhibits a high capacitance (253 mF/cm super(2)) in negative potentials (-1.0-0.0 V). The ASCs packaged with CF-Co(OH) sub(2) as a positive electrode and CF-WO sub(3)Py as a negative electrode display a high volumetric capacitance up to 2.865 F/cm super(3) based on volume of the device, an energy density of 1.02 mWh/cm super(3), and very good stability performance. These findings promote the application of PPy-based nanostructures as advanced negative electrodes for ASCs. Asymmetric supercapacitors (ASCs) packaged with CF-Co(OH) sub(2) as a positive electrode and CF-WO sub(3)Py as a negative electrode display a high volumetric capacitance up to 2.865 F cm super(-3) based on the volume of the device, an energy density of 1.02 mWh cm super(-3), and very stable performance. These findings promote the application of PPy-based nanostructures as advanced negative electrodes for ASCs.