Enhanced hydrogen storage properties of LiBH4–MgH2 composite by the catalytic effect of MoCl3

Though LiBH4–MgH2 system exhibits an excellent hydrogen storage property, it still presents high decomposition temperature over 350 °C and sluggish hydrogen absorption/desorption kinetics. In order to improve the hydrogen storage properties, the influence of MoCl3 as an additive on the hydrogenation and dehydrogenation properties of LiBH4–MgH2 system is investigated. The reversible hydrogen storage performance is significantly improved, which leads to a capacity of about 7 wt.% hydrogen at 300 °C. XRD analysis reveals that the metallic Mo is formed by the reaction between LiBH4 and MoCl3, which is highly dispersed in the sample and results in improved dehydrogenation and hydrogenation performance of LiBH4–MgH2 system. From Kissinger plot, the activation energy for hydrogen desorption of LiBH4–MgH2 system with additive MoCl3 is estimated to be ∼43 kJ mol−1 H2, 10 kJ mol−1 lower than that for the pure LiBH4–MgH2 system indicating that the kinetics of LiBH4–MgH2 composite is significantly improved by the introduction of Mo.

► The influence of MoCl3 as an additive on the hydrogenation and dehydrogenation properties of LiBH4–MgH2 was investigated.
►  The reversible hydrogen storage properties of LiBH4–MgH2 at 300 °C, with a capacity of about 7 wt.% hydrogen, was significantly improved by addition of MoCl3.
► The improved hydrogen storage properties of LiBH4–MgH2 is attributed to the formation of metallic Mo through the reaction of LiBH4 and MoCl3.