Speaker
Description
With hydrogen as energy carrier, hydrides are in the focus of research for the application of energy storage and energy transportation. Within the complex hydrides, the metal hydride composite Mg(NH2)2 + LiH has recently gained in importance because of good properties for reversible hydrogen storage. Mg(NH2)2 + LiH has faster de- and rehydrogenation kintetics with the addition of LiBH4. So far Mg(NH2)2 + LiH + LiBH4 is a good candidate to be used for hydrogen storage with the high capacity (ca. 4 wt%) and good reversibility.
To understand the effect of the LiBH4 additive on the kinetics, neutron scattering experiments were applied at the Heinz Maier-Leibnitz Zentrum (MLZ). With this poster we present the investigated quasielastic neutron scattering (QENS) and in-situ small angle neutron scattering (SANS) measurements.
At the TOFTOF instrument the Time-of-Flight spectroscopy of Li4BH4(NH2)3 was investigated, which is an intermediate of the dehydrogenated Mg(NH2)2 + LiH + LiBH4-system. This product showed in the QENS measurement high degree of freedom for rotational and transversal motions. With the high mobility of the BH4-tetrahedron, the fast absorption/desorption kinetics of the complex hydrides are explained.
In-situ SANS of Mg(NH2)2 + LiH + LiBH4 at SANS-1 instrument was measured. The analyzed sizes of the nanoparticles are preserved after hydrogenation/dehydrogenation reactions. In addition, a model for these reactions are proposed based on the in-situ measurements.
