Improved hydrogen storage properties of LiBH4 confined with activated charcoal by ball milling

Abstract

In order to enhance the hydrogen storage properties of LiBH4, activated charcoal (AC) was used as the scaffold to confine LiBH4 in this paper. Ball milling was used to prepare LiBH4/AC composites. Experimental results show that dehydrogenation properties of ball-milled LiBH4/AC (LiBH4/AC-BM) are greatly improved compared with that of pristine LiBH4, ball-milled LiBH4 (LiBH4-BM) and hand-milled LiBH4/AC (LiBH4/AC-HM). The onset dehydrogenation temperature of LiBH4 for LiBH4/AC-BM is around 160 °C, which is 170 °C lower than that of pristine LiBH4. At around 400 °C, LiBH4/AC-BM finishes the dehydrogenation with a hydrogen capacity of 13.6 wt%, which is approximately the theoretical dehydrogenation capacity of pure LiBH4 (13.8 wt%), while the dehydrogenation processes for LiBH4-BM and LiBH4/AC-BM do not finish even when they were heated to 600 °C. The isothermal dehydriding measurements show that it takes only 15 min for LiBH4/AC-BM to reach a dehydrogenation capacity of 10.1 wt% at 350 °C, whereas the pristine LiBH4 and the LiBH4/AC-HM release hydrogen less than 1 wt% under the same conditions. The dehydrogenation process and the effect of AC were discussed.