In this study, the positive effects and dual roles of SiB 4 on the dehydrogenation and rehydrogenation performance of the LiBH 4 -SiB 4 system are reported. Characterizations were performed through temperature programmed desorption mass spectrometry (TPD-MS), isothermal kinetics measurements, and XRD and FTIR analyses. For the hydrogen desorption from LiBH 4 , SiB 4 played the role of a catalyst to kinetically facilitate the structural destabilization of LiBH 4 and its intermediate phase Li 2 B 12 H 12 . Accordingly, a dehydrogenation capacity of 2.24 at. H/f.u. LiBH 4 (close to 10.3 wt% H) was attained at a relative temperature of 350 °C. For hydrogen absorption to generate LiBH 4 , SiB 4 was unexpectedly found to act as a reactant to thermodynamically improve the rehydrogenation process by reacting with LiH under moderate conditions of 10 MPa H 2 and 400 °C, and a superior reversible capacity of 2.16 at. H/f.u. LiBH 4 was achieved. These experimental results remind us to take into account the explicit role(s) of the employed components during the dehydrogenation and rehydrogenation reactions when designing a desirable LiBH 4 -based system.
ASJC Scopus subject areas
- Inorganic Chemistry