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.