LAUSR

Abstract The microstructure and self-discharge properties of Ce2Ni7-type La0.65Ce0.1Mg0.25Ni3Co0.5 hydrogen storage alloy produced by conventional casting, annealing and melt-spinning methods are studied. A melt-spun processing is greatly effective for improving the self-discharge properties by changing the microstructural evolution. The x-ray diffraction (XRD) analysis indicates that all three samples contain the major phase of (La, Mg)2Ni7 which belongs to the space group of P63/mmc, but the unit-cell volume of (La, Mg)2Ni7 phase for the melt-spun alloy is the smallest. The improvement of charge retention rate (CRR) for the three samples at 248 K is more significant than that at 298 K, especially for the melt-spun alloy. An increase of discharge-potential plateau leads to more reversible self-discharge of the alloy electrodes, corresponding to the corrosion degrees. Thus, the melt-spun alloy has the optimal self-discharge performance which is dominated by the reversible self-discharge process.