Investigation On Preparation And Hydrogen Storage Performance Of Mg-Li Solide Solution

In this paper,the Mg-Li alloys were prepared by the sintering and subsequently mechanical alloying methods to explore the effects of the preparation and catalytic doping on the Mg-Li phase structures,microstructures and hydrogen storage performances.Firstly,Mg90Li10-xSix(x=0,2,4,6),were synthesized via sintering and ball-milling.Analysis of the samples,via X-ray diffraction(XRD),revealed the presence of the Mg2Si phase because of the addition of Si.Moreover,measurements of the pressure-composition-isotherms(PCT)revealed the maximum reversible hydrogen storage capacities of 6.88 wt.%,5.69 wt.%,5.56 wt.%and 5.28 wt.%respectively,at 623 K,for the Mg90Li10-xSix(x=0,2,4,6)alloys.The Mg2Si acted as a catalyst that reducing the apparent activation energy(Ea),enhancing the reversible hydrogenation reaction,and improving the kinetic and thermodynamic performances of the Mg-Li solid solution.Secondly,Mg77Li23 alloy was prepared by sintering and ball milling.Then Mg77Li23+xwt.%Graphene(x=0,1,3,5)composite was prepared by ball milling and its hydrogen storage property was investigated.The results show that the particles size of Mg77Li23 alloys was decreased with the addition of Graphene through ball milling.The hydrogenation/dehydrogenation temperature and dehydrogenation activation energy were reduced with addition of Graphene.Graphene,as a catalyst,can effectively improved the kinetic and thermodynamic properties of Mg77Li23 alloys.Thirdly,the effects of Mg2Si and Graphene on the hydrogen storage properties of Mg77Li23 alloys were explored.Mg77Li23+5wt.%M(None,Mg2Si,Graphene,Graphene+Mg2Si)alloys were prepared by sintering and ball milling.The experimental results showed that the dehydrogrnation temperature is reduced by adding Mg2Si and Graphene.With the synergistic effect of Mg2Si and Graphene,the kinetic and thermodynamic performances of the Mg77Li23 alloys are improved.