Enhanced hydrogen storage capacity and reversibility of LiBH4 encapsulated in carbon nanocages

In this work, we first obtained carbon nanocages (CNCs) with nanoporous structure and high specific surface area via a template synthesis method, and then prepared a LiBH4@CNCs hydrogen storage composite by combining melting LiBH4 into the CNCs. Temperature programmed desorption (TPD) analyses show that the composite starts to release hydrogen at 200 degrees C, with the maximal desorption peak occurs at about 320 degrees C, which is 180 degrees C lower than that of the pure LiBH4. Also, the final hydrogen desorption capacity reaches 7.5 wt.%. We also see enhanced reversible properties of the composite, of which 78% initial hydrogen is absorbed after five de/rehydrogenation cycles at 400 degrees C. The further studies show that the LiBH4 can react with the oxygen-containing group of CNCs to form LiBo(2) during the infiltration process. The LiBo(2) dispersed on the scaffold of CNCs further reacts with LiBH4 to release more hydrogen, and the reaction product Li(3)Bo(3) as an efficient catalyst can significantly improve the reversible hydrogen storage properties of the LiBH4. The synergetic effect of nanoconfinement of CNCs and catalysis of Li(3)Bo(3) is proved to be largely beneficial for the decomposition process and reversible hydrogen absorption of LiBH4. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.