Unique hydrogen desorption properties of LiAlH4/h-BN composites

Abstract

Hexagonal boron nitride (h-BN) is known as an effective additive to improve the hydrogen de/absorption properties of hydrogen storage materials consisting of light elements. Herein, we report the unique hydrogen desorption properties of LiAlH4/h-BN composites, which were prepared by ball-milling. The desorption profiles of the composite indicated the decrease of melting temperature of LiAlH4, the delay of desorption kinetics in the first step, and the enhancement of the kinetics in the second step, compared with milled LiAlH4. Li3AlH6 was also formed in the composite after desorption in the first step, suggesting h-BN would have a catalytic effect on the desorption kinetics of Li3AlH6. Finally, the role of h-BN on the desorption process of LiAlH4 was discussed by comparison with the desorption properties of LiAlH4/X (X = graphite, LiCl and LiI) composites, suggesting the enhancement of Li ion mobility in the LiAlH4/h-BN composite.