Dehydriding and rehydriding properties of yttrium borohydride Y(BH4)3 prepared by liquid-phase synthesis

Y(BH4)3 was prepared by liquid-phase synthesis, and its dehydriding and rehydriding properties were systematically investigated by performing thermogravimetry and differential thermal analysis (TG-DTA) and powder X-ray diffraction (XRD) measurement. The dehydriding reaction of Y(BH4)3 starts at appropriately 460 K, and a total of 7.8 wt% of hydrogen is released up to 773 K. Phase transformation and melting are observed in Y(BH4)3 at approximately 474 K and 499 K, respectively. Both DTA and XRD measurement results indicate that the decomposition of Y(BH4)3 proceeds via multistep dehydriding reactions accompanied with the formation of an intermediate phase. Furthermore, Y(BH4)3 is proved to be partially rehydrided.