Lightweight hydrogen storage material

Recently, metal-doped aluminium hydrides have been proposed as further potential hydrogen storage materials [107, 123]. Among lightweight metal hydrides the lithium and sodium alanates (NaAfflU, LiAlH4) have been widely... 

I.P. Jain, P. Jain and A. Jain (2010) J. Alloys Compd., vol. 503, p. 303 - A review of lightweight metal hydrides as hydrogen storage materials. 

Fig. 6.2 The six basic hydrogen storage methods and phenomena. The gravimetric density prr, the volumetric density pv, the working temperature T and pressure p are listed. RT stands for room temperature (25°C). From top to bottom compressed gas (molecular H2) in a lightweight composite cylinder (tensile strength of the material is 2000 MPa) liquid hydrogen (molecular H2), continuous loss of a few percent per day of hydrogen at RT physisorption...

The discussion above was limited to alanates, borohydrides, amides, and combinations of these materials. Other hydrides or alternative approaches have also been proposed for storage applications. Zaluska et al. ° studied lightweight lithium-beryllium hydride and showed a reversible hydrogen capacity of over 8 wt%. They also showed that the hydride may be usable down to 150°C. Although these results are rather promising, it is unlikely that any beryllium-containing compound would be considered for vehicular use because of the toxicity of this element, even though the hydride may be quite stable. 

Compressed hydrogen can be fueled relatively fast, and the tanks can be reused many times. The main technical issues are the weight of the storage tank and the volume needed. Tank weight can be improved with the use of stronger and lightweight materials. Tank volume is improved by increasing the pressure. 

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