Investigations on hydrogen storage properties of Mg2Ni+x wt% LaMg2Ni (x=0, 10, 20, 30) composites

Abstract Mg 2 Ni+ x  wt% LaMg 2 Ni ( x =0, 10, 20, 30) composites have been prepared by ball milling Mg 2 Ni and LaMg 2 Ni hydrides. X-ray Diffraction indicates that the composites consist of LaH 3 and Mg 2 NiH 4 phases. Mg 2 NiH 4 phase transforms between with Mg 2 Ni phase during hydriding/dehydriding cycling, while the LaH 3 phase exists still after dehydriding process. Backscatter Electron results reveal that the LaH 3 phase, which is decomposed from hydrided LaMg 2 Ni, distributes in Mg 2 Ni alloy homogeneously after ball milling procedure. Hydriding/Dehydriding measurements indicate significant improvement in reversible hydrogen storage properties of the composites over Mg 2 Ni at low temperature. At 473 K, the hydrogen storage capacity of Mg 2 Ni+20 wt% LaMg 2 Ni composite reaches 3.22 wt% and can reversely desorb hydrogen completely, while the pure Mg 2 Ni hydride is hardly desorbs hydrogen at this temperature. The improvement in the hydrogen storage properties is attributed to the existence of LaH 3 phase in the composites.