Dehydrogenation Characteristics of Fe-, Co- and Ni-doped LiBH4: a Comparative First-Principles Study

This work involves a comparative first-principles calculation based on the density functional theory in order to provide a new insight into dehydrogenation characteristics of the transition metal (Fe, Co, Ni) doped LiBH4. Results showed that Fe, Co or Ni doping all can effectively improve the dehydrogenation performance of LiBH4 due to the weaker covalent bonding interaction between B-H and ionic bonding interaction between Li-B/H, especially the formation of Fe/Co/Ni-B bonds. For Li7MB8H32 (M=Li, Fe, Co, Ni) systems considered here, dehydrogenation energies are negatively correlated with electronegativity of metal M, i.e. an increase in electronegativity of metal M leads to a decrease of the system's dehydrogenation energy. Compared to Fe- and Co-doped systems, Ni-doped system, which has relatively low occupation energy and dehydrogenation energy according to the calculation, displays a satisfactory dehydrogenation performance. Our work has indicated from the perspective of computational simulation that combining LiBH4 with a metal element more electronegative than Li is an effective approach to the destabilization of LiBH4. © 2019,Materials Review Magazine. All right reserved.