Boosting the Dehydrogenation Properties of LiAlH₄ by Addition of TiSiO₄

Given its significant gravimetric hydrogen capacity advantage, lithium alanate (LiAlH₄) is regarded as a suitable material for solid-state hydrogen storage. Nevertheless, its outrageous decomposition temperature and slow sorption kinetics hinder its application as a solid-state hydrogen storage material. This research's objective is to investigate how the addition of titanium silicate (TiSiO₄) altered the dehydrogenation behavior of LiAlH₄. The LiAlH₄-10 wt% TiSiO₄ composite dehydrogenation temperatures were lowered to 92 °C (first-step reaction) and 128 °C (second-step reaction). According to dehydrogenation kinetic analysis, the TiSiO₄-added LiAlH₄ composite was able to liberate more hydrogen (about 6.0 wt%) than the undoped LiAlH₄ composite (less than 1.0 wt%) at 90 °C for 2 h. After the addition of TiSiO₄, the activation energies for hydrogen to liberate from LiAlH₄ were lowered. Based on the Kissinger equation, the activation energies for hydrogen liberation for the two-step dehydrogenation of post-milled LiAlH₄ were 103 and 115 kJ/mol, respectively. After milling LiAlH₄ with 10 wt% TiSiO₄, the activation energies were reduced to 68 and 77 kJ/mol, respectively. Additionally, the scanning electron microscopy images demonstrated that the LiAlH₄ particles shrank and barely aggregated when 10 wt% of TiSiO₄ was added. According to the X-ray diffraction results, TiSiO₄ had a significant effect by lowering the decomposition temperature and increasing the rate of dehydrogenation of LiAlH₄ via the new active species of AlTi and Si-containing that formed during the heating process.