Electrochemical study

of LaNi3.55Mn0.4Al0.3Fe0.75 negative electrode material

 

C. Khaldi1*, H. Mathlouthi1, J. Lamloumi1, A. Percheron-Guégan2

1L.M.M.P, ESSTT, 5 Avenue Taha Hussein 1008 Tunis, TUNISIE

2L.C.M.T.R, G.L.V.T, CNRS, 2-8 Rue Henri Dunant, 94320, Thiais Cedex, FRANCE

* Corresponding author. E-mail: chokri.khaldi@esstt.rnu.tn

Received: 10 October 2005; revised version accepted: 22 December 2007

Abstract

The electrochemical properties of LaNi3.55Mn0.4Al0.3Fe0.75 electrode have been investigated. A discharge capacity of 295 mAhg-1 at C/10 rate is obtained. A very great loss of capacity and therefore a considerable alloy decomposition may occur during the cycling, due to the corrosion process. The mechanism of the hydriding/dehydriding reaction on the alloy electrodes has also been investigated using a constant potential discharge (CPD), a cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The obtained values of the hydrogen diffusion coefficient DH, were, 1.1 10-10 cm2s-1, 1.0 10-10 cm2s-1 and 5.9 10-10 cm2s-1, by CV, CPD and EIS techniques respectively.

Keywords: Intermetallic hydride; Chronopotentiometry; constant potential discharge; cyclic voltammetry; impedance spectroscopy.

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