Destabilization of LiBH4 by (Ce, La)(Cl, F)3 for hydrogen storage

Research highlights: → Ce(BH4)3 and La(BH4)3 were obtained by ball milling LiBH4 + 1/3(Ce, La)Cl3 mixtures. → The dehydrogenation temperatures of ball milled LiBH4 + 1/3(Ce, La)(Cl, F)3 were decreased to 220-320 deg. C.→ Partial reversibility was achieved for LiBH4 + 1/3(Ce, La)(Cl, F)3. - Abstract: The mixtures of LiBH4 with halides of Ce or La in a molar ratio of 3:1 were investigated to explore their hydrogen storage properties. The ball milling of LiBH4 with chloride of Ce or La yielded Ce(BH4)3 and La(BH4)3, while fluoride of Ce or La did not react with LiBH4 during extended ball milling at room temperature. The dehydrogenation temperatures of the ball-milled mixtures were reduced to 220-320 deg. C, which were much lower than that of pure LiBH4. The diborane emission during hydrogen release was observed at a low level. The dehydrogenation temperature is found to be affected by the composition of rare earth halides, but less influenced by ball milling time. The endothermic dehydrogenation reactions produced lithium halides, hydrides and borides of the corresponding rare earth element. Moreover, the LiBH4 + 1/3(Ce, La)(Cl, F)3 showed partial reversibility through the formation of an unknown borohydride, allowing for a potential hydrogen storage system.