Lithium borohydride, LiBH4, possesses high hydrogen capacity, but cannot be used for hydrogen storage owing to the problematic H-exchange kinetics and thermodynamics. In the present study, we employed the Li +-Ca2+ combination strategy to improve the de/rehydrogenation properties of LiBH4. Our study found that mechanically milling 1:1 LiBH4/Ca(BH4)2 mixture formed a dual-cation borohydride, Li0.9Ca(BH4) 2.9, which then transformed to stoichiometric LiCa(BH 4)3 in the heating process. The formation and decomposition behaviors of LiCa(BH4)3 were studied using X-ray diffraction and thermogravimetry/differential scanning calorimetry/mass spectroscopy techniques. It was found that LiCa(BH4)3 differs significantly from the component phases in terms of physical properties, decomposition behaviors, and mechanistic pathway. In particular, LiCa(BH 4)3 exhibits improved de/rehydrogenation properties relative to the component phases. These experimental findings exemplified the effectiveness of manipulation of dual-cation combination in tuning the de/rehydrogenation properties of the ionic light-metal borohydrides.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films