High Li<sup>+</sup> and Na<sup>+</sup> Conductivity in New Hybrid Solid Electrolytes based on the Porous MIL‐121 Metal Organic Framework

Zettl, Roman; Lunghammer, Sarah; Gadermaier, Bernhard; Boulaoued, Athmane; Johansson, Patrik; Wilkening, H. Martin R.; Hanzu, Ilie

doi:10.1002/aenm.202003542

Cited by 36 publications

(36 citation statements)

References 94 publications

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“…Features being consistent with fast one-dimensional diffusion were found for

[ 93 ] and

[ 34 ]; in some cases, the presence of low-dimensional ion dynamics was unequivocally probed by frequency-dependent NMR SLR measurements [ 90 ]. Quite recently, the metal organic framework MIL-121 was functionalized such that fast Li and Na conduction occurs along the inner channels of the non-conducting host [ 94 ]. For the Na-MIL-121, ionic conductivities in the order of

0.1

were reached at room temperature.…”

Section: Case Studiesmentioning

confidence: 99%

Fuzzy logic: about the origins of fast ion dynamics in crystalline solids

Gombotz

Hogrefe

Zettl

et al. 2021

Phil. Trans. R. Soc. A.

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Nuclear magnetic resonance offers a wide range of tools to analyse ionic jump processes in crystalline and amorphous solids. Both high-resolution and time-domain 1 , 2 H , 6 , 7 Li , 19 F , 23 Na NMR helps throw light on the origins of rapid self-diffusion in materials being relevant for energy storage. It is well accepted that Li + ions are subjected to extremely slow exchange processes in compounds with strong site preferences. The loss of this site preference may lead to rapid cation diffusion, as is also well known for glassy materials. Further examples that benefit from this effect include, e.g. cation-mixed, high-entropy fluorides ( Ba, Ca) F 2 , Li-bearing garnets ( Li 7 La 3 Zr 2 O 12 ) and thiophosphates such as LiTi 2 ( PS 4 ) 3 . In non-equilibrium phases site disorder, polyhedra distortions, strain and the various types of defects will affect both the activation energy and the corresponding attempt frequencies. Whereas in ( Me, Ca ) F 2 ( Me = Ba , Pb ) cation mixing influences F anion dynamics, in Li 6 PS 5 X ( X = Br , Cl , I ) the potential landscape can be manipulated by anion site disorder. On the other hand, in the mixed conductor Li 4 + x Ti 5 O 12 cation-cation repulsions immediately lead to a boost in Li + diffusivity at the early stages of chemical lithiation. Finally, rapid diffusion is also expected for materials that are able to guide the ions along (macroscopic) pathways with confined (or low-dimensional) dimensions, as is the case in layer-structured RbSn 2 F 5 or MeSnF 4 . Diffusion on fractal systems complements this type of diffusion. This article is part of the Theo Murphy meeting issue ‘Understanding fast-ion conduction in solid electrolytes’.

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“…Features being consistent with fast one-dimensional diffusion were found for

[ 93 ] and

0.1

were reached at room temperature.…”

Section: Case Studiesmentioning

confidence: 99%

Fuzzy logic: about the origins of fast ion dynamics in crystalline solids

Gombotz

Hogrefe

Zettl

et al. 2021

Phil. Trans. R. Soc. A.

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“…This confers to the liquid phase very distinct ionic and physicochemical properties in the restricted space compared to the bulky material. 9 , 10 , 21 , 22 …”

Section: Introductionmentioning

confidence: 99%

Li⁺ Dynamics of Liquid Electrolytes Nanoconfined in Metal–Organic Frameworks

Farina

Duff

Tealdi

et al. 2021

ACS Appl. Mater. Interfaces

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Metal–organic frameworks (MOFs) are excellent platforms to design hybrid electrolytes for Li batteries with liquid-like transport and stability against lithium dendrites. We report on Li+ dynamics in quasi-solid electrolytes consisting in Mg-MOF-74 soaked with LiClO4–propylene carbonate (PC) and LiClO4–ethylene carbonate (EC)/dimethyl carbonate (DMC) solutions by combining studies of ion conductivity, nuclear magnetic resonance (NMR) characterization, and spin relaxometry. We investigate nanoconfinement of liquid inside MOFs to characterize the adsorption/solvation mechanism at the basis of Li+ migration in these materials. NMR supports that the liquid is nanoconfined in framework micropores, strongly interacting with their walls and that the nature of the solvent affects Li+ migration in MOFs. Contrary to the “free’’ liquid electrolytes, faster ion dynamics and higher Li+ mobility take place in LiClO4–PC electrolytes when nanoconfined in MOFs demonstrating superionic conductor behavior (conductivity σrt > 0.1 mS cm–1, transport number t Li+ > 0.7). Such properties, including a more stable Li electrodeposition, make MOF-hybrid electrolytes promising for high-power and safer lithium-ion batteries.

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“…As an alternative to earlier explanations, the change from 0.31 eV (at low T) toward 0.25 eV (at higher T) could also reflect a transition from correlated to less correlated motion. Such a transition has been used to explain similar kinks of Arrhenius lines in beta-alumina, 67 closo-borates 68 and metal organic frameworks 69 with Na + and Li + ions as the main charge carriers.…”

Section: Resultsmentioning

confidence: 99%

Ionic Conductivity of Nanocrystalline and Amorphous Li10GeP2S12: The Detrimental Impact of Local Disorder on Ion Transport

Hogrefe

Schweiger

Gadermaier

et al. 2021

Preprint

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Solid electrolytes with extraordinarily high Li-ionic conductivities are key for high performance all-solid-state batteries. So far, the thiophosphate Li10GeP2S12 (LGPS) belongs to the best Li ion conductors with an ionic conductivity exceeding 10 mS cm–1 at ambient. Recent molecular dynamics simulations performed by Dawson and Islam predict that the ionic conductivity of LGPS can be further enhanced by a factor of three if the crystallite size is reduced to the nanometer regime. A change in local ion coordination, hence local disorder, has been assumed to facilitate Li diffusion in the ab-plane of LGPS. As yet, no experimental evidence exists supporting this fascinating prediction. Here, we synthesized nanocrystalline LGPS by high-energy ball milling, characterized the material structurally and probed the Li+ ion transport parameters. Whereas X-ray powder diffraction and high-resolution 31P and 6Li magic angle spinning nuclear magnetic resonance (NMR) spectroscopy helped us to determine morphological changes and local structures upon milling, broadband conductivity spectroscopy in combination with electric modulus measurements allowed us to precisely follow the changes in Li+ ion dynamics. Surprisingly and against the behavior of other electrolytes, ionic conductivity turned out to decrease with increasing milling time, finally leading to a reduction of σ20°C by almost a factor of 10. This decrease affects both, bulk ion dynamics and total conductivity, which also comprises Li+ transport across grain boundary regions in LGPS. As could be shown by NMR, ball-milling leads to a structurally heterogeneous sample with the nm-sized LGPS crystallites being embedded in an amorphous matrix. This amorphous phase is responsible for the reduced performance of the milled electrolyte. Importantly, careful separation of the amorphous and (nano)crystalline contributions to the overall ionic conductivity revealed that even in the nanocrystalline regions Li+ ion dynamics is slowed down compared to untreated, coarse-grained LGPS. We conclude that defects introduced into the LGPS bulk structure via ball milling have a negative impact on ionic transport. We postulate that such kind of structural disorder is detrimental to fast ion transport in materials whose transport properties rely on crystallographically well-defined diffusion pathways.

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High Li⁺ and Na⁺ Conductivity in New Hybrid Solid Electrolytes based on the Porous MIL‐121 Metal Organic Framework

Cited by 36 publications

References 94 publications

Fuzzy logic: about the origins of fast ion dynamics in crystalline solids

Fuzzy logic: about the origins of fast ion dynamics in crystalline solids

Li⁺ Dynamics of Liquid Electrolytes Nanoconfined in Metal–Organic Frameworks

Ionic Conductivity of Nanocrystalline and Amorphous Li10GeP2S12: The Detrimental Impact of Local Disorder on Ion Transport

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High Li+ and Na+ Conductivity in New Hybrid Solid Electrolytes based on the Porous MIL‐121 Metal Organic Framework

Cited by 36 publications

References 94 publications

Fuzzy logic: about the origins of fast ion dynamics in crystalline solids

Fuzzy logic: about the origins of fast ion dynamics in crystalline solids

Li+ Dynamics of Liquid Electrolytes Nanoconfined in Metal–Organic Frameworks

Ionic Conductivity of Nanocrystalline and Amorphous Li10GeP2S12: The Detrimental Impact of Local Disorder on Ion Transport

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High Li⁺ and Na⁺ Conductivity in New Hybrid Solid Electrolytes based on the Porous MIL‐121 Metal Organic Framework

Li⁺ Dynamics of Liquid Electrolytes Nanoconfined in Metal–Organic Frameworks