Effect of LaCoO₃ Synthesized via Solid-State Method on the Hydrogen Storage Properties of MgH₂

One of the ideal energy carriers for the future is hydrogen. It has a high energy density and is a source of clean energy. A crucial step in the development of the hydrogen economy is the safety and affordable storage of a large amount of hydrogen. Thus, owing to its large storage capacity, good reversibility, and low cost, Magnesium hydride (MgH₂) was taken into consideration. Unfortunately, MgH₂ has a high desorption temperature and slow ab/desorption kinetics. Using the ball milling technique, adding cobalt lanthanum oxide (LaCoO₃) to MgH₂ improves its hydrogen storage performance. The results show that adding 10 wt.% LaCoO₃ relatively lowers the starting hydrogen release, compared with pure MgH₂ and milled MgH₂. On the other hand, faster ab/desorption after the introduction of 10 wt.% LaCoO₃ could be observed when compared with milled MgH₂ under the same circumstances. Besides this, the apparent activation energy for MgH₂-10 wt.% LaCoO₃ was greatly reduced when compared with that of milled MgH₂. From the X-ray diffraction analysis, it could be shown that in-situ forms of MgO, CoO, and La₂O_3, produced from the reactions between MgH₂ and LaCoO₃, play a vital role in enhancing the properties of hydrogen storage of MgH₂.