Thermal and mechanically activated decomposition of LiAlH4

Ares, J.R.; Aguey-Zinsou, Kondo Francois; Porcu, Martina; Sykes, J.M.; Dornheim, Martin; Klassen, Thomas; Bormann, R.

doi:10.1016/j.materresbull.2007.05.018

Cited by 75 publications

(81 citation statements)

References 44 publications

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“…Figure 5 shows the FT-IR spectra of 40 mass % h-BN composite and references. The as-milled composite showed the characteristic Al-H vibrations of LiAlH4 [22] around 1795 cm −1 and 1644 cm −1 . Also, B-N vibrations of h-BN around 1373 cm −1 and 818 cm −1 were observed.…”

Section: Resultsmentioning

confidence: 99%

Unique Hydrogen Desorption Properties of LiAlH4/h-BN Composites

et al. 2017

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Hexagonal boron nitride (h-BN) is known as an effective additive to improve the hydrogen de/absorption properties of hydrogen storage materials consisting of light elements. Herein, we report the unique hydrogen desorption properties of LiAlH 4 /h-BN composites, which were prepared by ball-milling. The desorption profiles of the composite indicated the decrease of melting temperature of LiAlH 4 , the delay of desorption kinetics in the first step, and the enhancement of the kinetics in the second step, compared with milled LiAlH 4 . Li 3 AlH 6 was also formed in the composite after desorption in the first step, suggesting h-BN would have a catalytic effect on the desorption kinetics of Li 3 AlH 6 . Finally, the role of h-BN on the desorption process of LiAlH 4 was discussed by comparison with the desorption properties of LiAlH 4 /X (X = graphite, LiCl and LiI) composites, suggesting the enhancement of Li ion mobility in the LiAlH 4 /h-BN composite.

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Section: Resultsmentioning

confidence: 99%

Unique Hydrogen Desorption Properties of LiAlH4/h-BN Composites

et al. 2017

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“…For each sample, the activation energies (E a ) of reactions (1) and (2) were estimated by the Kissinger method. 6,7) The activation energies of the two reactions are given by the slope fitting the equation: ln(b/T p 2 ) = (¹E a /RT p ) + ln(AR/E a ) (b = heating rate, T p = peak temperature of reaction obtained from DTA results, R = gas constant, and A = frequency factor). Figure 1 shows DTA curves of undoped and 2.0 mol% TiCl 3 samples under He flow at a heating rate of 20°C/min.…”

Section: Methodsmentioning

confidence: 99%

Additive Effects of TiCl<sub>3</sub> on Dehydrogenation Reaction of LiAlH<sub>4</sub>

et al. 2014

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Recently, LiAlH 4 has attracted attention as one of the most promising hydrogen storage materials, because LiAlH 4 is able to release large amount of hydrogen (7.9 mass%H 2 ) below 250°C. However, the kinetics of the dehydrogenation reaction of LiAlH 4 is too slow for applications to fuel cell vehicles. To improve the dehydrogenation kinetics, the dopant effect of TiCl 3 has been investigated in this research. Here, LiAlH 4 doped with various ratios (0, 0.1, 0.2, 0.5, 1.0, and 2.0 mol%) of TiCl 3 were prepared by ball milling for 30 min under a 1.0 MPa H 2 atmosphere. The decomposition of LiAlH 4 proceeds via a two-step reaction and the dehydrogenation kinetics of each step were compared to determine the optimum amount of TiCl 3 that would assist the process. With increasing of TiCl 3 amount, the dehydrogenation temperature for both of the reactions decreased. Activation energies decreased with increasing TiCl 3 amount, however the amount of desorbed hydrogen decreased. Considering the kinetics and hydrogen capacity in the both steps, the results suggest that the optimum amount of doped TiCl 3 for the dehydrogenation of LiAlH 4 is around 0.2 mol%.

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“…[43] Decomposition mechanism. As suggested by experimental data, [9,30] the decomposition of LiAlH 4 into Li 3 AlH 6 , Al, and H 2 , i.e., eqn (1), necessarily involves hydrogen and/or aluminum mass transport in the bulk. Besides, local and global charge neutrality must be maintained while charged defects are migrating.…”

Section: Ionic and Mass Transportmentioning

confidence: 98%

Decomposition mechanism and the effects of metal additives on the kinetics of lithium alanate

Hoang

Janotti

Walle

2012

Phys. Chem. Chem. Phys.

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First-principles density functional theory studies have been carried out for native defects and transition-metal (Ti and Ni) impurities in lithium alanate (LiAlH4), a potential material for hydrogen storage. On the basis of our detailed analysis of the structure, energetics, and migration of lithium-, aluminum-, and hydrogen-related defects, we propose a specific atomistic mechanism for the decomposition and dehydrogenation of LiAlH4 that involves mass transport mediated by native point defects. We also discuss how Ti and Ni impurities alter the Fermi-level position with respect to that in the undoped material, thus changing the concentration of charged defects that are responsible for mass transport. This mechanism provides an explanation for the experimentally observed lowering of the temperature for the onset of decomposition and of the activation energy for hydrogen desorption from LiAlH4.

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Thermal and mechanically activated decomposition of LiAlH4

Cited by 75 publications

References 44 publications

Unique Hydrogen Desorption Properties of LiAlH4/h-BN Composites

Unique Hydrogen Desorption Properties of LiAlH4/h-BN Composites

Additive Effects of TiCl<sub>3</sub> on Dehydrogenation Reaction of LiAlH<sub>4</sub>

Decomposition mechanism and the effects of metal additives on the kinetics of lithium alanate

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