Abstract
Given its significant gravimetric hydrogen capacity advantage, lithium alanate (LiAlH(4)) 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 (TiSiO(4)) altered the dehydrogenation behavior of LiAlH(4). The LiAlH(4)-10 wt% TiSiO(4) composite dehydrogenation temperatures were lowered to 92 °C (first-step reaction) and 128 °C (second-step reaction). According to dehydrogenation kinetic analysis, the TiSiO(4)-added LiAlH(4) composite was able to liberate more hydrogen (about 6.0 wt%) than the undoped LiAlH(4) composite (less than 1.0 wt%) at 90 °C for 2 h. After the addition of TiSiO(4), the activation energies for hydrogen to liberate from LiAlH(4) were lowered. Based on the Kissinger equation, the activation energies for hydrogen liberation for the two-step dehydrogenation of post-milled LiAlH(4) were 103 and 115 kJ/mol, respectively. After milling LiAlH(4) with 10 wt% TiSiO(4), the activation energies were reduced to 68 and 77 kJ/mol, respectively. Additionally, the scanning electron microscopy images demonstrated that the LiAlH(4) particles shrank and barely aggregated when 10 wt% of TiSiO(4) was added. According to the X-ray diffraction results, TiSiO(4) had a significant effect by lowering the decomposition temperature and increasing the rate of dehydrogenation of LiAlH(4) via the new active species of AlTi and Si-containing that formed during the heating process.