Hydrogen related peaks in Cu–LaNi4.7Al0.3

In this work, the effect of Ni substitution by Cu in the LaNi4.7Al0.3 hydride-forming alloy was studied in order to apply it to the negative electrodes of Ni–MH batteries. SEM, EDS and X-ray diffraction techniques were used to analyze the microstructure, composition and crystalline structure of the samples. A maximum electrochemical discharge capacity of 130 mAh/g was obtained.Internal friction (IF) and shear modulus (G) were measured by means of low frequency mechanical spectroscopy, between 100 and 450 K. In the electrochemical activated sample, two main IF peaks and typical relaxation steps in G showed up at 200 and 280 K. The first is ascribed to interactions between hydrides and H atoms in solid solution and dislocations, while the last one is attributed to the β ↔ α hydride phase transformation.