The hydrogen desorption kinetic mechanism of the Li–B–N–H system and the

catalytic role of metallic Co in this process were investigated systematically. It was

found that about 10wt% of hydrogen can be released from a 5wt%Co-doped

LiBH4/2LiNH2 sample to form a plate-like Li3BN2 product with dramatically

improved kinetics. A diffusion controlled kinetic mechanism for the

dehydrogenation reaction was identified by analyzing isothermal hydrogen

desorption processes with the Johnson–Mehl–Avrami equation. Introduction of

metallic Co into the LiBH4/2LiNH2 system decreased the melting temperature of

the α phase, catalyzed the formation of B–N bonds and facilitated nucleation and

growth of the dehydrogenated product. As a consequence, lower apparent

activation energy (about 94.8kJ/mol) for the sample with the Co additive was

obtained relative to the pristine sample (about 128.0kJ/mol). This lower activation

energy was responsible for the significant enhancement of the dehydrogenation

kinetics.

Diffusion Controlled Hydrogen Desorption Reaction for the LiBH4/2LiNH2 System.

Y.Liu, K.Luo, Y.Zhou, M.Gao, H.Pan: Journal of Alloys and Compounds, 2009,

481[1-2], 473-9