Beneficial effects of stoichiometry and nanostructure for a LiBH4–MgH2 hydrogen storage system

Abstract

The hydrogen storage system [MgH₂–2LiBH₄] shows attractive properties such as favorable thermodynamics, high hydrogen capacity and reversibility. However, there exists an incubation period that amounts up to 10 hours in the dehydrogenation steps, which restricts this system as a practical material. In this study, the influences of stoichiometry and the nanoscale MgH₂ were investigated for the system. Considerably shortened incubation times were achieved with deficit amounts of LiBH₄ or by using nanoscale MgH₂. In addition, the application of nanoscale MgH₂ prevented or suppressed the formation of [B₁₂H₁₂]²⁻ in the dehydrogenation, which is otherwise an issue concerning the re-cyclability.