Hydrogen storage alloys of La2-xSmxMg16Ni (x =0,0.1,0.2,0.3,0.4) were prepared by induction melting furnace.The alloy structure was analyzed by X-ray diffraction (XRD) before and after hydrogen absorption.The absorption/desorption hydrogen dynamics was investigated at different temperatures under pressure of 3 MPa.The activation energy of the alloy for absorption/desorption hydrogen was counted by Arrhenius means.The results showed that the main phase of the alloy was La2 Mg17 when La was partially replaced by Sm,and the second phase was SmNi and Sm5Mg41.LaH3 and MgH2 phases were found in the alloy after hydrogen absorption.With increase of Sm content,the maximum absorption hydrogen storage capacity and the absorption/desorption hydrogen dynamics kinetics were increasing.The hydrogen absorption capacity was 4.308％,4.342％,4.488％,4.564％,4.787％ (mass fraction,the same hereinafter),at 3 MPa and 498 K within 10 min.However,the hydrogen desorption capacity was 1.684％,1.521％,1.779％,1.666％,2.131％ in vacuum and 498 K within 20 min.The absorption/desorption hydrogen dynamics of the alloy was improved because Sm reduced the activation energy of the alloy.With the increase of Sm content in the alloy,the absolute value of formation enthalpy (△H) and hydrogen absorption platform pressure decreased firstly and then increased.The △H of La1.7 Sm0.3 Mg16 Ni alloys was the minimum value in prepared alloys,which was-53.07 kJ.mol-1.
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