Ultrafine-Grained Magnesium Alloys for Hydrogen Storage Obtained by Severe Plastic Deformation

Abstract

Magnesium alloys take a special place among the hydrogen storage materials, mainly due to their high gravimetric (7.6 mass %) and volumetric (110 kg m −3) hydrogen storage capacity. Unfortunately, the kinetics of hydrogenation and hydrogen release are rather slow, which limits practical use of magnesium-based materials for hydrogen and heat storage. Refining the microstructure of magnesium alloys, ideally down to nanoscale, is known to accelerate the hydrogenation/dehydrogenation kinetics. A possible way to achieve that is by severe plastic deformation. Our first demonstration of this effect through processing of a Mg alloy (ZK60) by equal-channel angular pressing prompted a stream of further studies employing severe plastic deformation techniques to improve the hydrogen storage-relevant properties of Mg alloys. The present article provides an overview of the literature on the subject, with a natural focus on our own data.

Impact of severe plastic deformation on kinetics and thermodynamics of hydrogen storage in magnesium and its alloys

“…The great benefit of ECAP is the possibility to obtain a promising hydrogen storage material in bulk, with an additional advantage of avoiding potentially hazardous ball milling of powders. Several studies utilizing ECAP as the processing route [33][34][35][36] and further SPD techniques were also applied to a range of Mg-based alloys [37,38], notably the eutectic Mg89Ni11 alloy with a fine lamellar structure [39].…”

Magnesium- and intermetallic alloys-based hydrides for energy storage: modelling, synthesis and properties

“…In a number of recent works, an appreciable acceleration of H sorption kinetics in the SPD-processed Mg and Mg-based alloys has been reported [127,[130][131][132][133]. The SPD process can accelerate the hydriding kinetics due to the several enhancement factors: (a) increased density of grain boundaries and dislocations serving as fast diffusion paths for H; (b) superior nucleation rate of the hydride phase (during hydriding) or metal phase (during dehydriding) due to heterogeneous nucleation on defects; (c) high activity of the defect surface sites (i.e.…”

“…Since the pioneering work of Skripnyuk et al [126] SPD methods have been widely employed for improving H storage properties of Mg-based alloys. A short review of the efforts in this field until the year 2018 was recently published by Rabkin et al [127]. In this respect, it should be noted that all attempts to improve the thermodynamics of hydriding with the aid of SPD were inconclusive.…”

Chemical material as a hydrogen energy carrier: A review

“…Notably, storing gaseous hydrogen at high pressure (350~700 bar) in storage tanks and transporting it via tube trailers is a prominent approach, as is liquefying gaseous hydrogen (−253 ℃) and storing it in dedicated storage tanks. These methods require specialized infrastructure due to the high energy density of hydrogen, and liquefaction, in particular, incurs significant energy consumption [46][47][48][49][50][51][52][53][54][55][56][57][58][59]. As alternatives, research is underway on physically adsorbing hydrogen onto porous materials such as Metal Organic Frameworks (MOFs) and Carbon nanotubes for storage and transportation, as well as chemically binding hydrogen to metals to enable solid-state storage and desorption, as seen in metal hydrides.…”