Molecular H2 trapped in AlH3 solid

Senadheera, Lasitha; Carl, Erik M.; Ivancic, Timothy M.; Conradi, Mark S.; Bowman, Robert C.; Hwang, Son‐Jong; Udovic, Terrence J.

doi:10.1016/j.jallcom.2007.08.071

Cited by 34 publications

(39 citation statements)

References 28 publications

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“…The amount of hydrogen obtained in the α phase is lower than that in nanocrystals 22 (4-6 nm, ~PdH 0.05 ) but close to that of bulk 23 (PdH 0.60 ), whereas for β phase it is lower than that obtained in bulk but higher than that in nanocrystals 22 To unequivocally establish the existence of molecular hydrogen in the nanocontainer, nuclear magnetic resonance ( 1 H solid state static NMR) study was carried out to augment the Raman experiments. The peak with a chemical shift of 2.29 ppm from sample-A3b (inset to Figure 4) corroborates well with the signature of molecular hydrogen 24 , thus firmly establishing our confidence in the presence of molecular hydrogen. The NMR signature from hydrogenated bulk Pd (broad peak) is also included for reference in the inset.…”

supporting

confidence: 76%

Multi-mode hydrogen storage in nanocontainers

Shervani

Mukherjee

Gupta

et al. 2017

International Journal of Hydrogen Energy

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supporting

confidence: 76%

Multi-mode hydrogen storage in nanocontainers

Shervani

Mukherjee

Gupta

et al. 2017

International Journal of Hydrogen Energy

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“…Most likely, these lines arise from compounds such as Li 2 B 10 H 10 or Li 2 B 12 H 12 . Alternatively, it has been suggested, at least for LiBH 4 /SiO 2 , that this line would be attributed to trapped H 2 , which is released as a result of a surface reaction between BH 4 – and the silanol groups at the surface of the oxide. , …”

Section: Results and Discussionmentioning

confidence: 99%

Li-Ion Diffusion in Nanoconfined LiBH₄-LiI/Al₂O₃: From 2D Bulk Transport to 3D Long-Range Interfacial Dynamics

Zettl

Gombotz

Clarkson

et al. 2020

ACS Appl. Mater. Interfaces

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Solid electrolytes based on LiBH 4 receive much attention because of their high ionic conductivity, electrochemical robustness, and low interfacial resistance against Li metal. The highly conductive hexagonal modification of LiBH 4 can be stabilized via the incorporation of LiI. If the resulting LiBH 4 -LiI is confined to the nanopores of an oxide, such as Al 2 O 3 , interface-engineered LiBH 4 -LiI/Al 2 O 3 is obtained that revealed promising properties as a solid electrolyte. The underlying principles of Li + conduction in such a nanocomposite are, however, far from being understood completely. Here, we used broadband conductivity spectroscopy and 1 H, 6 Li, 7 Li, 11 B, and 27 Al nuclear magnetic resonance (NMR) to study structural and dynamic features of nanoconfined LiBH 4 -LiI/Al 2 O 3 . In particular, diffusion-induced 1 H, 7 Li, and 11 B NMR spin–lattice relaxation measurements and 7 Li-pulsed field gradient (PFG) NMR experiments were used to extract activation energies and diffusion coefficients. 27 Al magic angle spinning NMR revealed surface interactions of LiBH 4 -LiI with pentacoordinated Al sites, and two-component 1 H NMR line shapes clearly revealed heterogeneous dynamic processes. These results show that interfacial regions have a determining influence on overall ionic transport (0.1 mS cm –1 at 293 K). Importantly, electrical relaxation in the LiBH 4 -LiI regions turned out to be fully homogenous. This view is supported by 7 Li NMR results, which can be interpreted with an overall (averaged) spin ensemble subjected to uniform dipolar magnetic and quadrupolar electric interactions. Finally, broadband conductivity spectroscopy gives strong evidence for 2D ionic transport in the LiBH 4 -LiI bulk regions which we observed over a dynamic range of 8 orders of magnitude. Macroscopic diffusion coefficients from PFG NMR agree with those estimated from measurements of ionic conductivity and nuclear spin relaxation. The resulting 3D ionic transport in nanoconfined LiBH 4 -LiI/Al 2 O 3 is characterized by an activation energy of 0.43 eV.

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“…The spectrum for pure Me 2 O at 0 °C (Fig. 5a) has a single broad resonance at 3.2 ppm, while after 48 h the peak for dissolved H 2 at 4.3 ppm [30] is still very small in comparison (Fig. 5b).…”

Section: Resultsmentioning

confidence: 95%

Regeneration of LiAlH4 at sub-ambient temperatures studied by multinuclear NMR spectroscopy

Humphries

Birkmire

McGrady

et al. 2017

Journal of Alloys and Compounds

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Lithium aluminium hydride (LiAlH 4 ) has long been identified as a viable hydrogen storage material, due to its high attainable theoretical gravimetric hydrogen capacity of 7.9 wt%.The main impediment to its viability for technical application is its limitation for regeneration. Recently, solvent-mediated regeneration has been achieved at room temperature using dimethyl-ether, Me 2 O, although the reaction pathway has not been determined. This in situ multinuclear NMR spectroscopy study ( 27 Al and 7 Li) has confirmed that the Me 2 O-mediated, direct synthesis of LiAlH 4 occurs by a one-step process in which LiAlH 4 ·xMe 2 O is formed, and does not involve Li 3 AlH 6 or any other intermediates.Hydrogenation has been shown to occur below ambient temperatures (at 0° C) for the first time, and the importance of solvate adducts formed during the process is demonstrated.

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Molecular H2 trapped in AlH3 solid

Cited by 34 publications

References 28 publications

Multi-mode hydrogen storage in nanocontainers

Multi-mode hydrogen storage in nanocontainers

Li-Ion Diffusion in Nanoconfined LiBH₄-LiI/Al₂O₃: From 2D Bulk Transport to 3D Long-Range Interfacial Dynamics

Regeneration of LiAlH4 at sub-ambient temperatures studied by multinuclear NMR spectroscopy

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Molecular H2 trapped in AlH3 solid

Cited by 34 publications

References 28 publications

Multi-mode hydrogen storage in nanocontainers

Multi-mode hydrogen storage in nanocontainers

Li-Ion Diffusion in Nanoconfined LiBH4-LiI/Al2O3: From 2D Bulk Transport to 3D Long-Range Interfacial Dynamics

Regeneration of LiAlH4 at sub-ambient temperatures studied by multinuclear NMR spectroscopy

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Li-Ion Diffusion in Nanoconfined LiBH₄-LiI/Al₂O₃: From 2D Bulk Transport to 3D Long-Range Interfacial Dynamics