Conditions to prepare PPy/Al2O3/Al used as a solid-state capacitor from aqueous malic solutions

• Type: Article in International Scientific Journal
• Date: 2006

Authors

José Inácio Martins (Author) FEUP; Costa, SC (Author) Other; Bazzaoui, M (Author) Other; Goncalves, G (Author) Other; Fortunato, E (Author) Other; Martins, R (Author) Other

Journal

Title: Journal of Power Sources

Vol. 160 No. 2

Pages: 1471-1479

ISSN: 0378-7753

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 11 Citations

ISI Web of Science

Scopus - 14 Citations

Other information

Authenticus ID: P-004-GMK

DOI: 10.1016/j.jpowsour.2006.03.020

Abstract (EN): The electrosynthesis of polypyrrole (PPy) has been achieved on aluminium in aqueous medium of malic acid by means of cyclic voltammetry, potentiostatic and galvanostatic techniques. Scanning electron microscopy (SEM) and X-ray microanalysis by dispersion energy spectroscopy (EDS) applying on surfaces show that the PPy coating is developed from the metal surface through the cracks of the initial Al2O3 layer. Moreover, the results reveal that the homogeneity of the film achieved increases with the time of electropolymerization. A mechanism involving the participation of the supporting electrolyte and the pyrrole (Py) in distinct active sites was proposed based on the linear sweep voltammetry. It is observed for all the applied electrochemical techniques that the pyrrole concentration has to be higher than 0.1 M to allow the polypyrrole electrodeposition in acid medium. Scanning electron microscopy, secondary electrons (SE) and backscattering electrons (BE), shows that the PPy coating obtained in galvanostatic and potentiostatic modes starts with small islands at weak applied potentials or current densities. The corrosion results in 3% NaCl medium show that the PPy coating decreases the corrosion behaviour of the aluminium. The bilayer Al2O3/PPY shows a capacitor with future applications.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 9