Abstract: A new series hydrogen storage alloys with elements Ce, Pr and Nd replacing La in alloy La0.8Mg0.2Ni2.8Co0.6 were obtained by electric induction melting. The addition of three rare earth elements has no significant influence on microstructures of the new alloys and the microstructures of new alloys are similar to that of La0.8Mg0.2Ni2.8Co0.6, LaNi5 phase with LaNi3 is as secondary phase; LaNi3 phase increases with the increases of amount of Ce, Pr, Nd. In La0.8-xRExMg0.2Ni2.8Co0.6 alloys the discharge capacities of the new alloys keep no change on 375mA·h/g, with only Pr addition to x=0.2; the other elements make the capacities decrease. The introduction of Ce, Pr makes the discharge voltage increases, while Nd shows less effect. Compared with the capacity decay rate of 1.07mA·h/(g·cycle) for the alloy La0.8Mg0.2Ni2.8Co0.6, the capacity decay rates of the new alloys are 0.566, 0.625 and 0.453mA·h/(g.cycle) with Ce, Pr and Nd addition to x=0.3, 0.6 and 0.6, respectively, which shows the stability of charging/discharging cycle is improved obviously.
Effects of rare earth elements on properties of La0.8Mg0.2Ni2.8Co0.6 hydrogen storage alloy
Abstract:
A new series hydrogen storage alloys with elements Ce, Pr and Nd replacing La in alloy La0.8Mg0.2Ni2.8Co0.6 were obtained by electric induction melting. The addition of three rare earth elements has no significant influence on microstructures of the new alloys and the microstructures of new alloys are similar to that of La0.8Mg0.2Ni2.8Co0.6, LaNi5 phase with LaNi3 is as secondary phase; LaNi3 phase increases with the increases of amount of Ce, Pr, Nd. In La0.8-xRExMg0.2Ni2.8Co0.6 alloys the discharge capacities of the new alloys keep no change on 375 mA·h/g, with only Pr addition to x=0.2; the other elements make the capacities decrease. The introduction of Ce, Pr makes the discharge voltage increases, while Nd shows less effect. Compared with the capacity decay rate of 1.07 mA·h/(g·cycle) for the alloy La0.8Mg0.2Ni2.8Co0.6, the capacity decay rates of the new alloys are 0.566, 0.625 and 0.453 mA·h/(g.cycle) with Ce, Pr and Nd addition to x=0.3, 0.6 and 0.6, respectively, which shows the stability of charging/discharging cycle is improved obviously.