MgH2 destabilization

JJ. Vajo, F. Mertens, C.C. Ahn, R.C. BowmanJr., B. Fultz, Altering hydrogen storage properties by hydride destabilization through alloy formation LiH and MgH2 destabilized with Si, . /. Phys. Chem. 108 (2004) 13977-13983. 

The comparison of the structure of Ti02 with that of MgH2 shows that the anatase-type structure has not yet been observed for MgH2 [97]. However, theoretical calculations of the assumed anatase structure exhibit a destabilized hydride compared with a-MgH2 (Figure 5.58). 

Very recently, Bystrzycki et al. [115] studied the possibility of destabilization of MgH2 by chemical reaction with Si and formation of an intermediate intermetallic... 

J. Bystrzycki, M. Polanski, T. Plocinski, Nano-engineering approach to destabilization of magnesium hydride (MgH2) by solid-state reaction with Si, . /. Nanosci. Nanotech. (2007) (in press). 

In order to find out if the decomposition of NaAlH4 destabilizes the MgH2 constituent in a composite, the peak temperatures of the last peak in a doublet/triplet in Fig. 3.38b-d which supposedly corresponds to the decomposition of MgH2 are plotted as a function of vol.%NaAlH4 in Fig. 3.39. It is quite clear that the ROM behavior for the MgH2 temperature is not obeyed for this composite system in contrast to the (MgH2 + LiAlH4) composite system. There are two factors which may be responsible for this behavior. 

It is relevant to point out that we have recently reported [203] a similar destabilization of MgH2 in a nanocomposite with NaBH4 synthesized by reactive mechanical milling of (Mg + Xwt%NaBH4) where X = 2, 10 and 20. In this nanocomposite... 

This is demonstrated in Fig. 3 by DSC measurements of MgH2. A fast cycle leads to a kinetically destabilized MgH2 [9]. By annealing the sample in hydrogen, the equilibrium state is reached. Accordingly, the onset temperatures defining the equilibrium plateau pressures differ significantly. 

A. Borgschulte, U. Bosenberg, G. Barkhordarian, M. Domheim and R. Bormann, Enhanced hydrogen sorption kinetics of magnesium by destabilized MgH2-s, Catal. Today 120 (2007) 262-269. 

Vajo et al. successfully demonstrated destabilization of LiBHt by using MgH2 as an additive [130]. The composite doped with TiQs is s)mthesized by ball-milling and reveals the reversible hydrogen ab/desorption of 8.0-10.0mass% as follows ... 

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