The structural properties of the potential battery electrode materials LaNi4Cu, LaNi4.4Cu, LaNi5Cu, and LaNi4.5Cu1.5 have been investigated by neutron and anomalous synchrotron powder diffraction. The nonstoichiometry of such ABx (5≤x≤6) compounds has been described in a structure derived from the hexagonal CaCu5-type structure by replacement of the A atoms by dumbbells of B atoms. In these copper-substituted compounds, Cu can occupy any of the four available nickel sites. From a joint refinement procedure using both neutron and synchrotron data, the copper-to-nickel ratio at each B site has been determined. This shows that substitution is not random and that copper occupies some crystallographic sites preferentially. The results are discussed and compared to other substituted AB5 systems.
|Journal||Zeitschrift fuer Kristallographie : International Journal for Structural, Physical and Chemical Aspects of Crystalline Materials|
|Publication status||Published - 1999|