Effect of Ti Intermetallic Catalysts on Hydrogen Storage Properties of Magnesium Hydride

Abstract

Magnesium hydride is a promising candidate for solid-state hydrogen storage and thermal energy storage applications. A series of Ti-based intermetallic alloy (TiAl, Ti3Al, TiNi, TiFe, TiNb, TiMn2, and TiVMn)-doped MgH2 materials were systematically investigated in this study to improve its hydrogen storage properties. The dehydrogenation and hydrogenation properties were studied by using both thermogravimetric analysis and pressure–composition–temperature (PCT) isothermal to characterize the temperature of dehydrogenation and the kinetics of both desorption and absorption of hydrogen by these doped MgH2. Results show significant improvements of both dehydrogenation and hydrogenation kinetics as a result of adding the Ti intermetallic alloys as catalysts. In particular, the TiMn2-doped Mg demonstrated extraordinary hydrogen absorption capability at room temperature and 1 bar hydrogen pressure. The PCT experiments also show that the hydrogen equilibrium pressures of MgH2 were not affected by these additives.

Stability and hydrogen adsorption properties of Mg/TiMn2 interface by first principles calculation

“…Our calculations show that the Mg-Ti interfacial zone appears as negative hydrogen adsorption energy [18]. The hydrogen storage properties can be improved by Ti-Mn intermetallics, in which the TiMn 2 participates in the de/hydrogenation process with remarkable hydrogenation kinetics at room temperature [19]. Previously, we found the formation of TiH 2 due to the strong bonding interactions between Ti and its neighboring H atoms and the great distortion of Mn alloyed MgH 2 will help to improve the dehydrogenation property of MgH 2 [20].…”

Metal hydrides based high energy density thermal battery

“…Details of the milling method and properties of the as-milled product can be found in our previous publication [16]. After milling, 50 g of TiMn 2 catalyzed MgH 2 was mixed with 5 wt.% expanded graphite (ENG).…”

“…Extensive research efforts, including optimization of the hydride materials, have been reported elsewhere [12,16,19]. Initially, in order to verify thermodynamic compatibility of the two hydride candidate materials, hydrogen equilibrium pressures of MgH 2 and TiMnV were characterized using a Sievert-type apparatus (PCT-Pro 2000).…”

“…However, pure MgH 2 , is known to have poor kinetic rates for both the dehydrogenation and hydrogenation reactions. Fortunately, recent progresses on hydrogen storage materials have shown that several nano-catalyzed Mg materials [12][13][14][15][16][17] are capable of absorbing a significant amount of hydrogen at room temperature. These findings have paved the way to practical application of Mg-based hydrides.…”

Synthesis of LiAlH4 Nanoparticles Leading to a Single Hydrogen Release Step upon Ti Coating

“…This impetus led to the current work which investigated a simple route for the synthesis of isolated LiAlH 4 nanoparticles and their stabilization for hydrogen cycling through a core-shell approach, with Ti acting as a shell facilitating the retention of molten LiAlH 4 upon dehydrogenation as well as a "gateway" for hydrogen absorption/desorption. Ti based additives have been widely studied via top-down ball milling for LiAlH 4 , as well as with other alanate systems e.g., NaAlH 4 and Mg(AlH 4 ) 2 with promising results, i.e., much improved hydrogen storage properties [21][22][23][24][25][26]. Indeed, Kojima et al determined the catalytic effects of various metal chlorides on LiAlH 4 , and revealed their positive effects in terms of hydrogen release in the order of TiCl 3 > ZrCl 4 > VCl 3 > NiCl 2 > ZnCl 2 [27].…”