Ali Nurul Amirah, Ahmad Muhammad Amirul Nawi, Yahya Muhammad Syarifuddin, Sazelee Noratiqah, Ismail Mohammad
Energy Storage Research Group, Faculty of Ocean Engineering Technology and Informatics, Universiti Malaysia Terengganu, Kuala Nerus 21030, Malaysia.
Nanomaterials (Basel). 2022 Nov 7;12(21):3921. doi: 10.3390/nano12213921.
Despite the application of lithium aluminium hydride (LiAlH4) being hindered by its sluggish desorption kinetics and unfavourable reversibility, LiAlH4 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 (CoTiO3) which was synthesised via a solid-state method on the desorption behaviour of LiAlH4. Superior desorption behaviour of LiAlH4 was attained with the presence of a CoTiO3 additive. By means of the addition of 5, 10, 15 and 20 wt.% of CoTiO3, the initial desorption temperature of LiAlH4 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 LiAlH4. The LiAlH4-CoTiO3 sample also presents outstanding desorption kinetics behaviour, desorbing hydrogen 30−35 times faster than undoped LiAlH4. The LiAlH4-CoTiO3 sample could desorb 3.0−3.5 wt.% H2 in 30 min, while the commercial and milled LiAlH4 desorbs <0.1 wt.% H2. The apparent activation energy of the LiAlH4-CoTiO3 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 LiAlH4. The LiAlH4-CoTiO3 sample presents uniform and smaller particle size distribution compared to undoped LiAlH4, which is irregular in shape with some agglomerations. The experimental results suggest that the CoTiO3 additive promoted notable advancements in the desorption performance of LiAlH4 through the in situ-formed AlTi and amorphous Co or Co-containing active species that were generated during the desorption process.
尽管氢化铝锂（LiAlH₄）的应用受到其缓慢的解吸动力学和不利的可逆性的阻碍，但由于其储氢容量（10.5 wt.%），LiAlH₄作为一种有前途的固态储氢材料受到了特别关注。在这项工作中，首次研究了通过固态法合成的纳米钛酸钴（CoTiO₃）对LiAlH₄解吸行为的影响。在CoTiO₃添加剂存在的情况下，LiAlH₄具有优异的解吸行为。通过添加5、10、15和20 wt.%的CoTiO₃，LiAlH₄第一阶段的初始解吸温度降至约115 - 120°C，第二解吸阶段降至约144 - 150°C，远低于未掺杂的LiAlH₄。LiAlH₄ - CoTiO₃样品还表现出出色的解吸动力学行为，解吸氢气的速度比未掺杂的LiAlH₄快30 - 35倍。LiAlH₄ - CoTiO₃样品在30分钟内可以解吸出3.0 - 3.5 wt.%的H₂，而商业化研磨的LiAlH₄解吸出的H₂ < 0.1 wt.%。基于基辛格分析，LiAlH₄ - CoTiO₃样品在第一和第二解吸阶段的表观活化能分别降至75.2和91.8 kJ/mol，比未掺杂的LiAlH₄分别低28.0和24.9 kJ/mol。与形状不规则且有一些团聚的未掺杂LiAlH₄相比，LiAlH₄ - CoTiO₃样品呈现出均匀且更小的粒度分布。实验结果表明，CoTiO₃添加剂通过在解吸过程中生成的原位形成的AlTi和无定形Co或含Co活性物种，促进了LiAlH₄解吸性能的显著提升。
