EIS study of MH negative electrode/electrolyte interface during cycling

Abstract

In this work, we studied, by electrochemical impedance spectroscopy (EIS), the metal hydride electrode/electrolyte interface associated with the LaY 2 Ni 9 and CeY 2 Ni 9 alloys during electrochemical cycling. Electrochemical impedance spectrum of the metal hydride electrode was interpreted by an equivalent circuit including the different electrochemical processes taking place on the interface between the MH electrode and the electrolyte. Electrochemical kinetic parameters such as the exchange current density, I0, and the double layer capacity, C dl , were determined during cycling for both the LaY 2 Ni 9 and CeY 2 Ni 9 alloy. The results of EIS measurements indicate that the electrochemical reaction activity of the LaY 2 Ni 9 metal hydride electrode is better than that of the CeY 2 Ni 9 alloy.