Borohydrides, hydrogen storage

Fig. 6.45 Schematic diagram of a borohydride hydrogen storage device for PEMFC.

B. H. Liu, S. Suda, Hydrogen storage alloys as the anode materials of the direct borohydride fuel ceU , J. Alloys Compd. 454 (2008) 280-285. 

Sodium borohydride contains 10.8 wt.% of hydrogen, but it shows unfavorable thermodynamics for use as reversible hydrogen storage material. Over 100 synthesis methods for the preparation of NaBH4 have been described, but only two have reached practical significance. In the Schlesinger process (Eq. (5.7)), trimethyl borate is boiled together with NaH in hydrocarbon oil at 250 °C [19] ... 

Zinc borohydride as an example of a transition metal compound contains 8.5 wt.% H2. The decomposition temperature of about 85 °C is quite low and is associated with the simultaneous melting of the compound. Between 85 and 140 °C an endothermic decomposition starts which is accompanied by the liberation of hydrogen and significant amounts of diborane. This excludes the use of Zn(BH4)2 for solid hydrogen storage [51]. 

SINGLE- AND DOUBLE-CATIONS BOROHYDRIDES FOR HYDROGEN STORAGE APPLICATIONS... 

Single- and Double-Cations Borohydrides for Hydrogen Storage Applications ... 

---