Abstract:In this paper, based on the first-principles density functional theory, the crystal structures, band stuctures and chemical bond properties of high-temperature phase(short for α-LiHB), low-temperature phase(short for β-LiHB) in LiN2H3BH3 and LiNH2BH3(short for LiAB) materials for hydrogen storage have been studied. The caculated hydrogen removal energies showed that Hδ+(N1), connected with Li , played a major role in the intial stage of dehydrogenation and low-temperature phase β-LiHB was easier to desorpt hydrogen than high-temperature phase α-LiHB. Then, HOMO and LUMO caculated by Dmol3 indicated that dehydrogenation of α-LiHB was through H-N1…B and H-N2…B, while β-LiHB and LiAB were only through H-N1…B. The energy gap of HOMO-LUMO suggested that chemicalSstability of LiAB, α-LiHB and β-LiHBH was: LiAB>α-LiHB>β-LiHB. All the researches provided theoretical basis for the synthesis of polyphase LiHB in some way.