Catalytic effect of SrTiO3 on the dehydrogenation properties of LiAlH4

Lithium alanate (LiAlH4) is regarded as one of the potential materials for on-board hydrogen storage applications because of its high hydrogen capacity. However, this advantage is restricted by several obstacles such as high decomposition temperature and slow desorption kinetics that deny its marketability. Hence, efforts such as decreasing the particle size by the mechanical milling technique and by adding dopants/catalysts have been investigated widely to overcome these drawbacks. In this work, the influences of strontium titanate (SrTiO3) on the dehydrogenation properties of LiAlH4 have been investigated for the first time. The onset decomposition temperature of the 10 wt% SrTiO3-doped LiAlH4 sample decreased from 145 degrees C to 80 degrees C in the first dehydrogenation step and from 178 degrees C to 120 degrees C in the second dehydrogenation step. For the desorption kinetic measurements at 90 degrees C, the 10 wt% SrTiO3 doped LiAlH4 sample could desorb about 3.0 wt% of H-2 in 20 min compared to 0.2 wt% by the as-milled LiAlH4. The activation energies calculated by Kissinger analysis in the two-step dehydrogenation process of LiAlH4 were lowered after the addition of SrTiO3. From the X-ray diffraction analysis, we found that SrTiO3 did not react during the mechanical milling and heating (desorption) processes. SrTiO3 is believed to play a catalytic role by reducing the physical size of LiAlH4 during the mechanical milling process thereby improving the dehydrogenation storage properties of LiAlH4. (C) 2020 Elsevier B.V. All rights reserved.