Effect of AB2-based alloy addition on structure and electrochemical properties of La0.5Pr0.2Zr0.1Mg0.2Ni2.75Co0.45Fe0.1Al0.2 hydrogen storage alloy

• Published in: Journal of rare earths Vol. 31; no. 4; pp. 386 - 394
• Main Author: 卢照 覃铭 蒋卫卿 卿培林 刘淑辉
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2013
• Subjects: AB2合金; Alloying additive; Ball milling; Current density; Discharge; electrochemical properties; Electrodes; Hydrogen storage; La-Mg-Ni-based alloy; Rare earth metals; rare earths; Scanning electron microscopy; X-射线衍射; Zr-based alloy; 合金电极; 合金结构; 扫描电子显微镜; 放电容量; 电化学性能; 贮氢; La-Mg-Ni-based alloy; Zr-based alloy; electrochemical properties; rare earths
• ISSN: 1002-0721; 2509-4963
• DOI: 10.1016/S1002-0721(12)60292-0

TheLa0.5Pr0.2Zr0.1Mg0.2Ni2.75Co0.45Fe0.1Al0.2（M0 and Zr0.65Ti0.35（Mn0.2V0.2Cr0.15Ni0.45）l.76 （M2） hydrogen storage alloys were prepared by inductive melting. In addition, the M1＋30 wt.%M2 composites were successively prepared by using high-energy ball milling technology. From the X-ray diffraction （XRD） analysis, it was found that M1 and M2 alloys still retained their respective main phases in the MI＋30 wt.%M2 composites. The scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS） indicated that the decrease in discharge capacity of MI and M2 alloy electrodes was ascribed to the oxidation-dissolution of La, Pr, Mg and Ti, Mn, V, Cr active elements, respectively. The electrochemical studies showed that the M1＋30 wt.%M2 composite electrode ball milling for 5 rain exhibited excellence cyclic stability （92.3%） after 80 charge/discharge cycles, which was higher than 77.7 % and 85.6% of MI and M2 alloy electrodes, respectively. Moreover, at the discharge current density of 1200 mA/g, the high rate dis- charge ability （HRD） of the M1＋30 wt.%M2 composite electrode increased from 61.5% （5 rain） to 70.3% （10 rain）. According to the linear polarization, Tafel polarization and cyclic voltammograms （CV）, the electrochemical kinetics of hydrogen reaction on the sur- face of the electrode and hydrogen diffusion rate in the bulk of alloy were also improved in the ML＋30 wt.%M2composite with in- creasing ball milling time.