HCS+MM法制备镁基复合储氢材料结构及储氢性能

Structures and Hydrogen Storage Properties of Magnesium-Based Composites

摘要:

采用氢化燃烧合成法制备Mg95Ni5-x%TiFe0.8Mn0.2Zr0.05(x=0, 10, 20, 30)(质量分数)复合物，然后将氢化燃烧合成产物进行机械球磨得到镁基复合储氢材料。采用XRD、SEM、EDS及PCT研究材料的相结构、表面形貌、颗粒化学成分以及吸放氢性能。研究表明，添加30% TiFe0.8Mn0.2Zr0.05合金形成的复合物具有最佳的综合吸放氢性能：在373 K，50 s内基本达到饱和吸氢量4.11% (质量分数)；在493和523 K，1800 s内放氢量分别为1.91%和4.3%；其起始放氢温度为420 K，与Mg95Ni5相比降低了20 K，吸放氢性能的改善与复合物的组织结构密切相关。此外，TiFe0.8Mn0.2Zr0.05的加入改善了复合物的放氢动力学性能

Abstract:

Mg95Ni5-x%TiFe0.8Mn0.2Zr0.05 (x = 0, 10, 20, 30) (mass fraction) composites were prepared by hydriding combustion synthesis (HCS) and the products were mechanically milled (MM) to obtain Mg-based hydrogen-storage composites. By means of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS) and pressure-composition-temperature (PCT) measurements, the phase structure, microstructure, particle composition and hydriding/dehydriding properties of the composites were studied. Results show that the Mg95Ni5-30%TiFe0.8Mn0.2Zr0.05 composite has the best comprehensive hydriding/dehydridingn properties. It requires only 50 s to absorb its saturated hydrogen capacity of 4.11 wt% at 373 K and desorbs 1.91 wt% and 4.3 wt% hydrogen within 1800 s at 493 K and 523 K, respectively. Moreover, the dehydriding onset temperature of the composite is 420 K, which is 20 K lower than that of Mg95Ni5. The improvement of hydriding/dehydriding properties are related greatly to the structures of the composites, and the addition of TiFe0.8Mn0.2Zr0.05 can improve the dehydriding kinetics of the composites.