Effect of carbon support on the kinetic behaviour of a metal hydride electrode

• Published in: Electrochimica acta 2009-02, Vol.54 (7), p.2010-2017
• Main Authors: Thomas, J.E., Andreasen, G., Arenillas, A., Zubizarreta, L., Barath, P., Sedlaříková, M., Vondrak, J., Visintin, A.
• Format: Article
• Language: English
• Subjects: Applied sciences; Batteries; Carbon nanotubes; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Hydride alloys; Hydrogen
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2008.08.061

The possibility to improve the electrochemical behaviour of AB 5-alloy commercial electrodes was studied using different carbons as support, such as carbon blacks and a selection of commercial and in-lab synthesised carbon nanotubes. The carbons selected for this work present different morphologies (i.e., spherical and tubular). Furthermore, they also present a variation of the porous structure and subsequent surface area, which are also going to influence their further electrochemical behaviour. Carbon samples were texturally characterised by the adsorption–desorption of N 2 and CO 2 at 77 and 273 K, respectively. The carbon structure was analysed by XRD, Raman, TEM, and the chemistry of the samples was also characterised by elemental analysis. The charge and discharge techniques, cyclic voltammetry, rate capability and linear polarisation were used for the electrochemical characterisation of the electrodes studied. The electrochemical behaviour of all the samples was related to their morphological, textural and chemical properties. The results show that there is a clear influence of the nature of the carbon support on the hydriding/dehydriding reaction of the alloy, and in the case of active carbons the kinetics decreases with the increase of the surface area of the carbon support.