Theoretical and Experimental Research of Hydrogen Solid Solution in Mg and Mg-Al System.

Jinzhe Lyu,Viktor N Kudiiarov,Leonid A Svyatkin,Roman R Elman

doi:10.3390/ma15051667

Jinzhe Lyu, Viktor N Kudiiarov + Show 2 more

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https://doi.org/10.3390/ma15051667

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Abstract

The study of hydrogen storage properties of Mg-based thin films is of interest due to their unique composition, interface, crystallinity, and high potential for use in hydrogen-storage systems. Alloying Mg with Al leads to the destabilization of the magnesium hydride reducing the heat of reaction, increases the nucleation rate, and decreases the dehydriding temperature. The purpose of our study is to reveal the role of the aluminum atom addition in hydrogen adsorption and accumulation in the Mg-H solid solution. Ab initio calculations of aluminum and hydrogen binding energies in magnesium were carried out in the framework of density functional theory. Hydrogen distribution and accumulation in Mg and Mg-10%Al thin films were experimentally studied by the method of glow-discharge optical emission spectroscopy and using a hydrogen analyzer, respectively. It was found that a hydrogen distribution gradient is observed in the Mg-10%Al coating, with more hydrogen on the surface and less in the bulk. Moreover, the hydrogen concentration in the Mg-10%Al is lower compared to Mg. This can be explained by the lower hydrogen binding energy in the magnesium-aluminum system compared with pure magnesium.

Highlights

As a high-energy-density and clean energy source, hydrogen energy has attracted increasing attention
Analysis of the obtained experimental data showed that a hydrogen distribution gradient is observed in the magnesium-aluminum coating, with more hydrogen on the surface and less in the bulk
This is due to the fact that the hydrogen binding energy in the magnesium-aluminum system is significantly lower compared to pure magnesium

Summary

Introduction

As a high-energy-density and clean energy source, hydrogen energy has attracted increasing attention. Tremendous efforts have been devoted to decreasing the diffusion barrier and hydrogenation temperature rate, including doping catalysts [14,15,16,17,18,19,20] and synthesis of nanostructured composites [20,21,22,23,24]. Such methods as melting, sintering, or mechanochemical synthesis by ball milling are used to achieve these goals for magnesium. At present, many research groups continue their work on the study of the hydrogen storage properties of Mg-based thin films, for which one can refer to our previous review [26]

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