A NaAlH4-Ca(BH4)2 composite system for hydrogen storage

Abstract

© 2017 Mechanochemical treatment (ball-milling) of NaAlH4-Ca(BH4)2mixtures leads to partial formation of NaBH4and Ca(AlH4)2by a metathesis reaction. The reaction proceeds to different extents depending on the applied ball-milling times, which is confirmed by powder X-ray diffraction and infrared spectroscopy. Additionally, an in-situ synchrotron radiation powder X-ray diffraction study reveals that the metathesis reaction continues due to thermal treatment while the data also supports a two-step decomposition of the formed Ca(AlH4)2. Finally, the reactive hydride composite system was investigated by mass spectrometry and Sieverts' measurement, which reveal release of ~6 wt% H2at T < 400 °C.