Enhanced Desorption and Absorption Properties of Eutectic LiBH4-Ca(BH4)(2) Infiltrated into Mesoporous Carbon

Abstract

We present enhanced hydrogen storage properties of the eutectic LiBH4-Ca(BH4)(2) composite confined inside a mesoporous carbon scaffold via melt infiltration. The eutectic composition was examined by analyzing the enthalpy of fusion as a function of the LiBH4-to-Ca(BH4)(2) ratio. Elemental analysis by energy dispersive X-ray spectroscopy and phase analysis by X-ray diffraction patterns provided both direct and indirect evidence for the infiltration of the LiBH4-Ca(BH4)(2) composite into the mesoporous channels of the carbon. The major dehydrogenation event occurred at similar to 300 degrees C, which is lower compared with the same composite without carbon or previously reported pure LiBH4 confined in mesoporous carbons. Without additional catalytic additives, almost half of the initial hydrogen capacity was recovered after one cycling. This improved performance is a synergistic effect of the nanoconfinement and the mutual destabilization between LiBH4 and Ca(BH4)(2), and it also indicates that the eutectic melting phenomenon can be exploited as an effective way of coinfiltration of reactive hydride composites.