Hydrogen storage properties of Mg-BCC composite

MgH2 with 10 wt% Ti0.4Mn0.22Cr0.1V0.28 (termed BCC for its body-centered cubic structure) nanocomposite was fabricated by ball milling using different ball-to-powder weight ratios. The X-ray diffraction patterns make it clear that pure Mg powder is partly transformed to MgH2, while by adding the BCC, its hydriding becomes complete. The scanning electron microscope images showed that the BCC particles were uniformly dispersed on the surface of the Mg particles. Differential scanning calorimetry traces of the samples showed that the addition of the BCC obviously decreases the desorption temperature, and an additional decrease is observed from increasing the ball-to-powder weight ratio. The hydriding/dehydriding and the pressure-composition isotherm curves indicate significant improvement in the absorption/desorption kinetics and the hydrogen storage capacity of MgH2 from both adding the BCC and increasing the ball-to-powder weight ratio. The results indicate that the BCC acts as a medium that facilitates hydrogen absorption during hydrogenation on Mg, thus improving hydrogen storage capacity and absorption/desorption kinetics.