Comparative study of by powder microelectrode technique

In order to understand the effect of different B-site partial substitution without the influence of calendar corrosion, the overall electrochemical performance of LaNi 4.7 M 0.3 ( M = Ni , Co , Mn , Al ) alloys were rapidly evaluated by means of a powder microelectrode technique (PME). The cell parameters of the alloys were also measured by XRD for a better understanding of the substitution effects. The study results show that the activation cycle is shortened by Mn partial substitution for Ni and prolonged by Co and Al partial substitution and reveal that the effect of the partial substitution of Ni improves the cycling performance in the order Co > Al > Mn and enhances the anti-electro-oxidation ability in the order Mn < Al < Co , while decreases the maximum discharge ability and the hydrogen diffusion coefficient in the order Co > Mn > Al , and raises the polarization of the alloy discharge reaction in the order Co > Mn > Al . The different substitution effects mainly result from the difference in the physical properties of the substituting metals (such as Vickers hardness and atomic size) and the properties of the substituting metal oxides formed on the alloy surface.