论文部分内容阅读
The influence of elemental composition on the crystal structure, hydrogen storage and electrochemical properties for Mg-containing alloys was investigated. As La/Mg ratio decreased, the slight change of Ni content was detected. XRD results indicated that these alloys were composed of LaNi 5 and Mg-containing phases. The lattice parameters of Mg-containing phases decreased. Meanwhile, the mass fraction of Mg-containing phases varied with the change of La/Mg and Ni. The hydrogen storage capacity reached ～1.6 wt.% for La/Mg≧ 3 :1 and decreased to ～0.71 wt.% for La/Mg=1. Two hydrogen absorption processes were observed because of the existence of the multiphases for La/Mg≧ 3 :1. With decreasing La/Mg ratio, the equilibrium pressurerose due to the shrinkage of the lattice parameter. Meanwhile, one hydrogen absorption process was obviously present. The discharge capacity of these as-cast alloys was higher, but the cyclic stability was poor for La/Mg≧ 3 :1 due to the partial amorphisation. It was better for La/Mg≤2 although the discharge capacity was lower. The polarization resistance increased, contrarily the exchange current density decreased with decreasing Mg content.
The influence of elemental composition on the crystal structure, hydrogen storage and electrochemical properties for Mg-containing alloys was investigated. As La / Mg ratio decreased, the slight change in Ni content was detected. XRD results indicated that these alloys were composed of LaNi 5 The mass fraction of Mg-containing phases varied with the change of La / Mg and Ni. The hydrogen storage capacity reached ~ 1.6 wt.% for La / Mg ≧ 3: 1 and decreased to ~ 0.71 wt.% For La / Mg = 1. Both hydrogen absorption processes were observed because of the existence of the multiphases for La / Mg ≧ 3: 1. With decreasing La / Mg ratio, the The pressure capacity due these as-cast alloys was higher, but the cyclic stability was poor for La / Mg ≧ 3: 1 due to the partial amorphis It was better for La / Mg≤2 although the discharge capacity was lower. The polarization resistance increased, contrarily the exchange current density decreased with decreasing Mg content.