Lanial Hydrogen Storage Alloy Modified

Heat-treatment and surface modification of Cu-coating and SiO₂-coating for LaNiAl hydrogen storage alloys were studied in this paper. X-ray diffraction (XRD), SEM, XPS, absorption and desorption hydrogen and Electrochemical Impedance Spectroscopy (EIS) were used to study and analyze systematically the relationship between the microstructure, electrochemical performances of hydrogen storage alloy and modifying treatment. The results are shown as following:(1) LaNiAl alloys prepared by electric arc melting were heated at 1040℃for 24h. Alloy annealed eliminated segregation in the alloys and lessened internal pressure, and as a result smoothened the hydrogen absorption/desorption platform of the alloys; annealing enlarged crystal lattice volume and resulting in the deterioration of the circle performance is restrained.(2) Surface Cu coating enhanced the speed of hydrogen absorption/desorption considerably, and the hydrogen absorption content reduced a little, while no evident pulverization can be found in this alloy after 10 hydrogen absorption/desorption cycles. Alloy coating with Cu also shrew excellent electrochemical performance, such as high discharge voltage and stable cycle performance.(3) Alloys with SiO₂ coating also showed excellent pulverization resistance. And absorption content was almost the same as nude LaNi_4.25Al_0.75 alloys but speed of hydrogen absorption/desorption obviously enhanced. The cycle stability enhanced, while discharge voltage lowed.