Nanostructures of LiBH4: a density-functional study

The phase stability and electronic structure of alpha-LiBH4-derived nanostructures and possible low energy surfaces of thin films have been investigated using the ab initio projected augmented plane wave method. Structural optimizations based on total energy calculations predicted that, for the alpha-LiBH4 phase, the (010) surface is the most stable of the possible low-energy surfaces. The predicted critical sizes of the nano-cluster and nano-whisker for alpha-LiBH4 are 1.75 and 1.5 nm, respectively. Similarly, the bond distances in the surfaces of a nano-whisker are found to be higher than that in the bulk material. The calculated hydrogen site energies suggest that it is relatively easier to remove hydrogen from the surface of the clusters and nano-whiskers than from bulk crystals.