Improved Dehydrogenation Properties of LiAlH 4 by Addition of Nanosized CoTiO 3 .

Despite the application of lithium aluminium hydride (LiAlH 4 ) being hindered by its sluggish desorption kinetics and unfavourable reversibility, LiAlH 4 has received special attention as a promising solid-state hydrogen storage material due to its hydrogen storage capacity (10.5 wt.%). In this work, investigated for the first time was the effect of the nanosized cobalt titanate (CoTiO 3 ) which was synthesised via a solid-state method on the desorption behaviour of LiAlH 4 . Superior desorption behaviour of LiAlH 4 was attained with the presence of a CoTiO 3 additive. By means of the addition of 5, 10, 15 and 20 wt.% of CoTiO 3 , the initial desorption temperature of LiAlH 4 for the first stage was reduced to around 115-120 °C and the second desorption stage was reduced to around 144-150 °C, much lower than for undoped LiAlH 4 . The LiAlH 4 -CoTiO 3 sample also presents outstanding desorption kinetics behaviour, desorbing hydrogen 30-35 times faster than undoped LiAlH 4 . The LiAlH 4 -CoTiO 3 sample could desorb 3.0-3.5 wt.% H 2 in 30 min, while the commercial and milled LiAlH 4 desorbs <0.1 wt.% H 2 . The apparent activation energy of the LiAlH 4 -CoTiO 3 sample based on the Kissinger analysis was decreased to 75.2 and 91.8 kJ/mol for the first and second desorption stage, respectively, lower by 28.0 and 24.9 kJ/mol than undoped LiAlH 4 . The LiAlH 4 -CoTiO 3 sample presents uniform and smaller particle size distribution compared to undoped LiAlH 4 , which is irregular in shape with some agglomerations. The experimental results suggest that the CoTiO 3 additive promoted notable advancements in the desorption performance of LiAlH 4 through the in situ-formed AlTi and amorphous Co or Co-containing active species that were generated during the desorption process.