Rapid evaluation of LaNi5−xMnx (x = 0.1–0.5) by X-ray diffraction and powder microelectrode (PME) techniques

LaNi5−xMnx (x = 0.1–0.5) were systematically investigated by both X-ray diffraction and powder microelectrode (PME) techniques. The results of XRD study show that both the lattice parameters and the cell volume of the alloy increase linearly with increasing the amount of Mn substitution. PME study of the alloys can be finished in a very short time (less than 10 h for each sample), thus it avoids the calendar corrosion of Mn and gives more true information about the function of Mn partial substitution for Ni. The results of PME study show that Mn partial substitution for Ni shortens the activation cycle, improves the cycling performance, decreases the maximum discharge ability and diffusion coefficient, and increases the overpotential of the alloy electrode. The calendar corrosion occurred on composite alloy electrodes should be responsible for the discrepancy between the results of this work and those of the previous ones.