Sol-gel template synthesis of highly ordered MnO2 nanowire arrays

• Published in: Journal of power sources 2005-01, Vol.140 (1), p.211-215
• Main Authors: XINGYAN WANG, XIANYOU WANG, WEIGUO HUANG, SEBASTIAN, P. J, GAMBOA, Sergio
• Format: Article
• Language: English
• Subjects: Applied sciences; Capacitors. Resistors. Filters; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Various equipment and components
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2004.07.033

In this paper, anodic aluminum oxide (AAO) templates with uniform pore diameter and periodicity were fabricated using a two-step oxidizating method at a constant current of 1.5Adm-2 in a mixed solution of 0.5M sulfate acid and 5gL-1 oxalic acid at room temperature, pore-widening was done in 5wt.% phosphoric acid. Then, arrays of manganese dioxide nanowires were prepared by combining the AAO template and a sol-gel solution containing Mn(CH3COO)2 and citric acid. SEM was used to characterize the structure of AAO and MnO2 nanowires. The results show that uniform length and diameter of MnO2 nanowires were obtained, and the length and diameter of MnO2 nanowires are dependent on the pore diameter and the thickness of the applied AAO template. The pore diameter of the AAO was about 70nm, the diameter of the MnO2 nanowires was 70nm and the length of the MnO2 nanowires was about 500-700nm. XRD analysis indicate the MnO2 nanowires was alpha-MnO2 polymorph. The results of cyclic voltammetry indicated that the alpha-MnO2 nanowires are promising electrode materials for application in supercapacitors, the specific capacity of the electrode was 165Fg-1.