Boosting the Dehydrogenation Properties of LiAlH4 by Addition of TiSiO4

Abstract

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.

Improved dehydrogenation performance of LiAlH4 doped with BaMnO3

“…Two regions of Al–H modes were discovered (i) [AlH 4 ] − bending at 800−900 cm −1 and (ii) [AlH 4 ] − stretching at 1600−1800 cm −1 . A similar study was disclosed by Yusnizam et al [ 55 ] which observed that a new peak at 1403 cm −1 was detected which shows that the addition of TiSiO 4 could weak the Al–H bond of LiAlH 4 .

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