Microstructure and electrochemical properties of La 0.8–x MM x Mg 0.2 Ni 3.1 Co 0.3 Al 0.1 ( x = 0, 0.1, 0.2, 0.3) alloys

摘要: The present study aims to improve electrochemical properties of the La–Mg–Ni-based hydrogen storage alloys through partial substitution for La by mischmetal (MM). La0.8–x MM x Mg0.2Ni3.1Co0.3Al0.1 (x = 0, 0.1, 0.2, 0.3) were prepared inductive melting, and their phase structures studied X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive spectrometry (EDX) tests. Results show that mainly consist La2Ni7-type phase, La5Ni19-type LaNi5-type LaNi3-type phase. addition MM does not change compositions, while it leads more uniform distribution obviously promotes formation which possesses favorable properties. Electrochemical studies indicate could effectively high rate dischargeability (HRD) alloy electrode, optimal value HRD1500 (HRD at 1500 mA·g−1) increases from 40.63 % (x = 0) 60.55 % (x = 0.3). Although activation electrodes keep almost unchanged, both maximum discharge capacity (C max) cycling stability are significantly improved addition.