KNOTEK Vítězslav ICT Prague

Influence of Rare Earth and Transition Metals on Electrochemical Hydriding of Mg-based Alloys

Co-authors VOJTĚCH Dalibor

The main task for using hydrogen as energy carrier is its storage. Magnesium alloys, as efficient hydrogen storage materials, have attracted great attentions recently. Magnesium is light, inexpensive and non-toxic metal. The main advantage of magnesium for hydrogen storage is its ability to absorb up to 7.6 wt. % of hydrogen in the form of magnesium hydride. However, magnesium hydride suffers from high thermodynamic stability and slow hydriding kinetics, which limit its practical application. To improve thermodynamics and kinetics of magnesium hydride, the alloying of magnesium by transition and rare earth metals is often employed. In this study, several as-cast Mg-based alloys alloyed by rare-earth and transition metals were hydrided by the electrochemical hydriding method. Since electrochemical hydriding requires neither high temperature nor gaseous hydrogen, the application for hydrogen storage seems to be very perspective. The electrochemical hydriding was carried out in a 6 M KOH solution at 80 °C for 480 min and at 100 A/m2. The microstructure of both as cast and hydrided alloys were investigated by optical and scanning electron microscopy and by X-ray diffraction. The concentrations of absorbed hydrogen in the alloys were measured by glow discharge spectrometry. The influence of microstructure and alloying metals on ability of magnesium alloys to absorb hydrogen were evaluated.