Electrochemical studies on LaNi4.15Co0.43Mn0.40Fe0.02 metal hydride alloy

Electrochemical studies were performed on LaNi4.15Co0.43Mn0.40Fe0.02. alloy electrode. The kinetics of the electrochemical hydrogen absorption/desorpt ion reaction was studied by DC polarization and AC impedance measurements. In a low overpotential range the reaction is charge-transfer controlled whi le in a high-overpotential range, the combine mechanism, charge-transfer an d hydrogen diffusion in the bulk of the alloy is operative. Both exchange c urrent, I-0, and hydrogen diffusion coefficient, D, slightly increase with hydrogen concentration in the alloy electrode. (C) 2000 Elsevier Science S. A. All rights reserved.