Improved hydrogen storage properties of Mg-Li-Al-H composite system by milling with Fe2O3 powder

A sample of Fe2O3-doped 4MgH(2)-Li3AlH6 composite was prepared by the ball milling technique, and the hydrogen storage properties were investigated for the first time. Results showed that the addition of Fe2O3 powder reduced the decomposition temperature and improved de/hydrogenation kinetics compared with undoped 4MgH(2)-Li3AlH6. The onset decomposition temperature for the Fe2O3-doped 4MgH(2)-Li3AlH6 composite decreased by 75 degrees C compared with that of the undoped composite. For the sorption kinetics, a hydrogen absorption capacity of 2.4 wt% was reached after 60 min in the 10 wt% Fe2O3-doped 4MgH(2)-Li3AlH6 composite, whereas the neat composite absorbed 2.3 wt% hydrogen under the same conditions. For desorption kinetics, the Fe2O3-doped 4MgH(2)-Li3AlH6 sample released 2.5 wt% hydrogen under 10 min of dehydrogenation, but the neat 4MgH(2)-Li3AlH6 composite only desorbed 2.0 wt% hydrogen within the same period. The apparent activation energy calculated by Kissinger analysis for hydrogen desorption decreased to 112.9 kJ/mol after Fe2O3 was added compared with the undoped composite, which was 145.4 kJ/mol. The X-ray diffraction analysis shows the formation new phase of Li2Fe3O4 in the doped sample after ball milling processes that could act as the real catalyst in the Fe2O3-doped 4MgH(2)-Li3AlH6 composite. (C) 2017 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.