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Abstract
Abstract
Ionic redistribution at solid interfaces in ionic materials is the keystone of nanoionics. An experimental master piece has been provided by CaF2-BaF2 heterolayers. Meanwhile this system and the involved heterojunctions are extraordinarily well-understood. The present paper gives an account of this model system by reviewing not only transport experiments and defect-chemical modeling as a function of temperature and spacing of the individual layers, but also transition from semi-infinite to mesoscopic conditions, transition from Mott–Schottky to Gouy–Chapman behavior as well as the impact of ionic redistribution on the electronic minority carriers. Owing to the availability of bulk transport data, the analysis works well for in-plane and out-of-plane measurements with only the space charge potential as fit parameter. Space charge effects are able to provide an interpretation of the annealing behavior, too. The experiments are corroborated by molecular dynamics simulations. Extrapolating the ionic redistribution effects down to the atomic level may even explain homovalent doping effects in non-equilibrium mixtures of the two fluorides.
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Affiliation(s)
- Rotraut Merkle
- Max Planck Institute for Solid State Research , Heisenbergstr. 1, 70569 Stuttgart , Germany
| | - Joachim Maier
- Max Planck Institute for Solid State Research , Heisenbergstr. 1, 70569 Stuttgart , Germany
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2
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Gombotz M, Hogrefe K, Zettl R, Gadermaier B, Wilkening HMR. Fuzzy logic: about the origins of fast ion dynamics in crystalline solids. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2021; 379:20200434. [PMID: 34628947 PMCID: PMC8503637 DOI: 10.1098/rsta.2020.0434] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 06/07/2021] [Indexed: 05/27/2023]
Abstract
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 [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] NMR helps throw light on the origins of rapid self-diffusion in materials being relevant for energy storage. It is well accepted that [Formula: see text] 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 [Formula: see text], Li-bearing garnets ([Formula: see text]) and thiophosphates such as [Formula: see text]. 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 [Formula: see text] ([Formula: see text]) cation mixing influences F anion dynamics, in [Formula: see text] ([Formula: see text]) the potential landscape can be manipulated by anion site disorder. On the other hand, in the mixed conductor [Formula: see text] cation-cation repulsions immediately lead to a boost in [Formula: see text] 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 [Formula: see text] or [Formula: see text]. 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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Affiliation(s)
- M. Gombotz
- Institute for Chemistry and Technology of Materials, Christian Doppler Laboratory for Lithium Batteries, Graz University of Technology (NAWI Graz), Stremayrgasse, 9, 8010 Graz, Austria
| | - K. Hogrefe
- Institute for Chemistry and Technology of Materials, Christian Doppler Laboratory for Lithium Batteries, Graz University of Technology (NAWI Graz), Stremayrgasse, 9, 8010 Graz, Austria
| | - R. Zettl
- Institute for Chemistry and Technology of Materials, Christian Doppler Laboratory for Lithium Batteries, Graz University of Technology (NAWI Graz), Stremayrgasse, 9, 8010 Graz, Austria
| | - B. Gadermaier
- Institute for Chemistry and Technology of Materials, Christian Doppler Laboratory for Lithium Batteries, Graz University of Technology (NAWI Graz), Stremayrgasse, 9, 8010 Graz, Austria
| | - H. Martin. R. Wilkening
- Institute for Chemistry and Technology of Materials, Christian Doppler Laboratory for Lithium Batteries, Graz University of Technology (NAWI Graz), Stremayrgasse, 9, 8010 Graz, Austria
- ALISTORE – European Research Institute, CNRS FR3104, Hub de l’Energie, Rue Baudelocque, 80039 Amiens, France
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3
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Gombotz M, Hogrefe K, Wilkening A, Gadermaier B, Wilkening M. F anion transport in nanocrystalline SmF3 and in mechanosynthesized, vacancy-rich Sm1—x
BaxF3—x. Z PHYS CHEM 2021. [DOI: 10.1515/zpch-2021-3092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Nanostructured materials can show considerably different properties as compared to their coarse-grained counterparts. Especially prepared by high-energy ball milling they are to be characterized by a large fraction of point defects in the bulk and structurally disordered interfacial regions. Here, we explored how the overall conductivity of SmF3 can be enhanced by mechanical treatment and to which degree aliovalent substitution is able to further enhance anion transport. For this purpose nanocrystalline (hexagonal) SmF3 was prepared by high-energy ball milling; mechanosynthesis helped us to replace Sm3+ in SmF3 by Ba2+ and to create vacancies in the F anion sublattice. We observed a remarkable increase in total (direct current) conductivity when going from nano-SmF3 to Sm1−x
Ba
x
F3−x
for x = 0.1. Electrical modulus spectroscopy was used to further characterize the corresponding increase in electrical relaxation frequencies.
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Affiliation(s)
- Maria Gombotz
- Institute of Chemistry and Technology of Materials, Graz University of Technology , Stremayrgasse 9, 8010 , Graz , Austria
| | - Katharina Hogrefe
- Institute of Chemistry and Technology of Materials, Graz University of Technology , Stremayrgasse 9, 8010 , Graz , Austria
| | - Alexandra Wilkening
- Institute of Chemistry and Technology of Materials, Graz University of Technology , Stremayrgasse 9, 8010 , Graz , Austria
| | - Bernhard Gadermaier
- Institute of Chemistry and Technology of Materials, Graz University of Technology , Stremayrgasse 9, 8010 , Graz , Austria
| | - Martin Wilkening
- Institute of Chemistry and Technology of Materials, Graz University of Technology , Stremayrgasse 9, 8010 , Graz , Austria
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4
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Scholz G. Mechanochemistry of fluoride solids: from mechanical activation to mechanically stimulated synthesis. CHEMTEXTS 2021. [DOI: 10.1007/s40828-021-00133-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
This lecture text is focused on the comparatively young field of mechanochemistry of fluoride solids, considering both their mechanical activation and their mechanochemical synthesis. Beside a literature survey, the mechanochemical synthesis of binary fluorides MF2, MF3, of complex fluorides MMgF4, of solid solutions MaxMb1−xF2 or M1−xLnxF2+x (Ln: Y, Eu) and of fluorine-containing coordination polymers is presented. Owing to their interesting potential applications in the field of fluoride ion conductivity or luminescence properties when doped, most of the given examples are alkaline earth metal compounds. A short historical survey, remarks on peculiarities and consequences of mechanical activation as well as the necessary technical equipment for mechanochemical reactions precede the section.
Graphic abstract
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5
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Buchinskaya II, Ivanovskaya NA. Mechanosynthesis of Fluorite Solid Solution in the PbF2–CdF2 System. CRYSTALLOGR REP+ 2020. [DOI: 10.1134/s1063774520060103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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6
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Brinek M, Hiebl C, Wilkening HMR. Understanding the Origin of Enhanced Li-Ion Transport in Nanocrystalline Argyrodite-Type Li 6PS 5I. CHEMISTRY OF MATERIALS : A PUBLICATION OF THE AMERICAN CHEMICAL SOCIETY 2020; 32:4754-4766. [PMID: 32565618 PMCID: PMC7304077 DOI: 10.1021/acs.chemmater.0c01367] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 05/18/2020] [Indexed: 05/05/2023]
Abstract
Argyrodite-type Li6PS5X (X = Cl, Br) compounds are considered to act as powerful ionic conductors in next-generation all-solid-state lithium batteries. In contrast to Li6PS5Br and Li6PS5Cl compounds showing ionic conductivities on the order of several mS cm-1, the iodine compound Li6PS5I turned out to be a poor ionic conductor. This difference has been explained by anion site disorder in Li6PS5Br and Li6PS5Cl leading to facile through-going, that is, long-range ion transport. In the structurally ordered compound, Li6PS5I, long-range ion transport is, however, interrupted because the important intercage Li jump-diffusion pathway, enabling the ions to diffuse over long distances, is characterized by higher activation energy than that in the sibling compounds. Here, we introduced structural disorder in the iodide by soft mechanical treatment and took advantage of a high-energy planetary mill to prepare nanocrystalline Li6PS5I. A milling time of only 120 min turned out to be sufficient to boost ionic conductivity by 2 orders of magnitude, reaching σtotal = 0.5 × 10-3 S cm-1. We followed this noticeable increase in ionic conductivity by broad-band conductivity spectroscopy and 7Li nuclear magnetic relaxation. X-ray powder diffraction and high-resolution 6Li, 31P MAS NMR helped characterize structural changes and the extent of disorder introduced. Changes in attempt frequency, activation entropy, and charge carrier concentration seem to be responsible for this increase.
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7
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Düvel A. Ionic conductivity and structure of M 1-xPb xF 2 (M = Ca, Sr, Ba) solid solutions prepared by ball milling. Dalton Trans 2019; 48:859-871. [PMID: 30475375 DOI: 10.1039/c8dt03759k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Nanocrystalline M1-xPbxF2 (M = Ca, Sr, Ba) solid solutions were prepared by ball milling mixtures of binary parent materials. The structure of the obtained materials was investigated by 19F MAS NMR spectroscopy and XRPD, and their ionic conductivity by impedance spectroscopy. It was found that fluorite-structured solid solutions over the whole range of compositions can be prepared by ball milling for all three systems, closing the broad miscibility gap of the CaF2-PbF2 system. The fluoride ion conductivity increased with increasing Pb content of the solid solutions, with Ba0.10Pb0.90F2 showing the highest conductivity of all samples prepared, being 1.5 orders of magnitude smaller than the one of PbSnF4. Ca1-xPbxF2 showed a fluoride ion conductivity increase which can be assigned to geometric frustration induced disorder. Ball milling of pure PbF2 revealed an increase of the fluoride ion conductivity by 2.5 orders of magnitude in the case of PbF2 containing a large amount of β-PbF2 compared to microcrystalline β-PbF2. Its fluoride ion conductivity is also 2.5 orders of magnitude larger than the fluoride ion conductivity of ball milled PbF2 consisting of a small amount of β-PbF2 but a large amount of α-PbF2 pointing to differently conducting and structured grain boundaries of α-PbF2 and β-PbF2.
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Affiliation(s)
- Andre Düvel
- Institute of Physical Chemistry and Electrochemistry, Leibniz University Hannover, Callinstr. 3.3a, 30167 Hannover, Germany.
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8
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Doughty B, Genix AC, Popov I, Li B, Zhao S, Saito T, Lutterman DA, Sacci RL, Sumpter BG, Wojnarowska Z, Bocharova V. Structural correlations tailor conductive properties in polymerized ionic liquids. Phys Chem Chem Phys 2019; 21:14775-14785. [DOI: 10.1039/c9cp02268f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this paper, it was demonstrated that the mobile ion (anion) size and pendant group chemistry affect the packing of the polymer chains and influence conductivity in imidazolium based PolyILs.
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Affiliation(s)
- Benjamin Doughty
- Chemical Sciences Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | - Anne-Caroline Genix
- Laboratoire Charles Coulomb (L2C), Université de Montpellier
- CNRS
- F-34095 Montpellier
- France
| | - Ivan Popov
- Chemical Sciences Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | - Bingrui Li
- Department of Chemistry
- University of Tennessee
- Knoxville
- USA
| | - Sheng Zhao
- Department of Chemistry
- University of Tennessee
- Knoxville
- USA
| | - Tomonori Saito
- Chemical Sciences Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | | | - Robert L. Sacci
- Chemical Sciences Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
| | - Bobby G. Sumpter
- Center for Nanophase Materials Sciences
- Oak Ridge National Laboratory
- Oak Ridge
- USA
- Computational Sciences & Engineering Division
| | - Zaneta Wojnarowska
- Chemical Sciences Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
- Institute of Physics
| | - Vera Bocharova
- Chemical Sciences Division
- Oak Ridge National Laboratory
- Oak Ridge
- USA
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9
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Fluorine Translational Anion Dynamics in Nanocrystalline Ceramics: SrF2-YF3 Solid Solutions. CRYSTALS 2018. [DOI: 10.3390/cryst8030122] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Breuer S, Wilkening M. Mismatch in cation size causes rapid anion dynamics in solid electrolytes: the role of the Arrhenius pre-factor. Dalton Trans 2018; 47:4105-4117. [DOI: 10.1039/c7dt04487a] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Mixed (Ba,Ca)F2 reveals highly correlated F anion diffusion in disordered potentials landscapes.
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Affiliation(s)
- Stefan Breuer
- Christian Doppler Laboratory for Lithium Batteries and Institute for Chemistry and Technology of Materials
- Graz University of Technology (NAWI Graz)
- 8010 Graz
- Austria
| | - Martin Wilkening
- Christian Doppler Laboratory for Lithium Batteries and Institute for Chemistry and Technology of Materials
- Graz University of Technology (NAWI Graz)
- 8010 Graz
- Austria
- ALISTORE-ERI European Research Institute
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11
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Düvel A, Heitjans P, Fedorov P, Scholz G, Cibin G, Chadwick AV, Pickup DM, Ramos S, Sayle LWL, Sayle EKL, Sayle TXT, Sayle DC. Is Geometric Frustration-Induced Disorder a Recipe for High Ionic Conductivity? J Am Chem Soc 2017; 139:5842-5848. [PMID: 28362104 DOI: 10.1021/jacs.7b00502] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Andre Düvel
- Institute
of Physical Chemistry and
Electrochemistry, Leibniz Universität Hannover, Callinstrasse
3-3a, D-30167 Hannover, Germany
- School
of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, U.K
| | - Paul Heitjans
- Institute
of Physical Chemistry and
Electrochemistry, Leibniz Universität Hannover, Callinstrasse
3-3a, D-30167 Hannover, Germany
| | - Pavel Fedorov
- General Physics Institute of Russian Academy of Sciences, 119991 Moscow, Russia
| | - Gudrun Scholz
- Department
of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, D-12489, Berlin, Germany
| | - Giannantonio Cibin
- Diamond
Light Source, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, U.K
| | - Alan V. Chadwick
- School
of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, U.K
| | - David M. Pickup
- School
of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, U.K
| | - Silvia Ramos
- School
of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, U.K
| | - Lewis W. L. Sayle
- School
of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, U.K
| | - Emma K. L. Sayle
- School
of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, U.K
| | - Thi X. T. Sayle
- School
of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, U.K
| | - Dean C. Sayle
- School
of Physical Sciences, University of Kent, Canterbury, Kent CT2 7NH, U.K
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12
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Prutsch D, Breuer S, Uitz M, Bottke P, Langer J, Lunghammer S, Philipp M, Posch P, Pregartner V, Stanje B, Dunst A, Wohlmuth D, Brandstätter H, Schmidt W, Epp V, Chadwick A, Hanzu I, Wilkening M. Nanostructured Ceramics: Ionic Transport and Electrochemical Activity. ACTA ACUST UNITED AC 2017. [DOI: 10.1515/zpch-2016-0924] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractCeramics with nm-sized dimensions are widely used in various applications such as batteries, fuel cells or sensors. Their oftentimes superior electrochemical properties as well as their capabilities to easily conduct ions are, however, not completely understood. Depending on the method chosen to prepare the materials, nanostructured ceramics may be equipped with a large area fraction of interfacial regions that exhibit structural disorder. Elucidating the relationship between microscopic disorder and ion dynamics as well as electrochemical performance is necessary to develop new functionalized materials. Here, we highlight some of the very recent studies on ion transport and electrochemical properties of nanostructured ceramics. Emphasis is put on TiO
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13
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Wilkening M, Düvel A, Preishuber-Pflügl F, da Silva K, Breuer S, Šepelák V, Heitjans P. Structure and ion dynamics of mechanosynthesized oxides and fluorides. ACTA ACUST UNITED AC 2016. [DOI: 10.1515/zkri-2016-1963] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
In many cases, limitations in conventional synthesis routes hamper the accessibility to materials with properties that have been predicted by theory. For instance, metastable compounds with local non-equilibrium structures can hardly be accessed by solid-state preparation techniques often requiring high synthesis temperatures. Also other ways of preparation lead to the thermodynamically stable rather than metastable products. Fortunately, such hurdles can be overcome by mechanochemical synthesis. Mechanical treatment of two or three starting materials in high-energy ball mills enables the synthesis of not only new, metastable compounds but also of nanocrystalline materials with unusual or enhanced properties such as ion transport. In this short review we report about local structures and ion transport of oxides and fluorides mechanochemically prepared by high-energy ball-milling.
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Affiliation(s)
- Martin Wilkening
- Institute for Chemistry and Technology of Materials (member of NAWI Graz), Graz University of Technology, Stremayrgasse 9, A-8010 Graz, Austria
- Institute of Physical Chemistry and Electrochemistry, Leibniz Universität Hannover, Callinstraße 3-3a, D-30167 Hannover, Germany
| | - Andre Düvel
- Institute of Physical Chemistry and Electrochemistry, Zentrum für Festkörperchemie und Neue Materialien (ZFM), Leibniz Universität Hannover, Callinstraße 3-3a, D-30167 Hannover, Germany
| | - Florian Preishuber-Pflügl
- Institute for Chemistry and Technology of Materials (member of NAWI Graz), Graz University of Technology, Stremayrgasse 9, A-8010 Graz, Austria
| | - Klebson da Silva
- Institute of Physical and Theoretical Chemistry, Technische Universität Braunschweig, Hans-Sommer-Str. 10, D-38106 Braunschweig, Germany
- Institute of Physical Chemistry and Electrochemistry, Leibniz Universität Hannover, Callinstr. 3-3a, D-30167 Hannover, Germany
- Department of Physics of Materials, State University of Maringá, Av. Colombo 5790, 87020900 Maringá, Brazil
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Stefan Breuer
- Institute for Chemistry and Technology of Materials (member of NAWI Graz), Graz University of Technology, Stremayrgasse 9, A-8010 Graz, Austria
| | - Vladimir Šepelák
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Paul Heitjans
- Institute of Physical Chemistry and Electrochemistry, Zentrum für Festkörperchemie und Neue Materialien (ZFM), Leibniz Universität Hannover, Callinstraße 3-3a, D-30167 Hannover, Germany
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14
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Preishuber-Pflügl F, Wilkening M. Mechanochemically synthesized fluorides: local structures and ion transport. Dalton Trans 2016; 45:8675-87. [PMID: 27172256 DOI: 10.1039/c6dt00944a] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The performance of new sensors or advanced electrochemical energy storage devices strongly depends on the active materials chosen to realize such systems. In particular, their morphology may greatly influence their overall macroscopic properties. Frequently, limitations in classical ways of chemical preparation routes hamper the development of materials with tailored properties. Fortunately, such hurdles can be overcome by mechanochemical synthesis. The versatility of mechanosynthesis allows the provision of compounds that are not available through common synthesis routes. The mechanical treatment of two or three starting materials in high-energy ball mills enables the synthesis not only of new compounds but also of nanocrystalline materials with unusual properties such as enhanced ion dynamics. Fast ion transport is of crucial importance in electrochemical energy storage. It is worth noting that mechanosynthesis also provides access to metastable phases that cannot be synthesized by conventional solid state synthesis. Ceramic synthesis routes often yield the thermally, i.e., thermodynamically, stable products rather than metastable compounds. In this perspective we report the mechanochemical synthesis of nanocrystalline fluorine ion conductors that serve as model substances to understand the relationship between local structures and ion dynamics. While ion transport properties were complementarily probed via conductivity spectroscopy and nuclear magnetic relaxation, local structures of the phases prepared were investigated by high-resolution (19)F NMR spectroscopy carried out by fast magic angle spinning. The combination of nuclear and non-nuclear techniques also helped us to shed light on the mechanisms controlling mechanochemical reactions in general.
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Affiliation(s)
- Florian Preishuber-Pflügl
- Institute for Chemistry and Technology of Materials, DFG-SPP 1415, Graz University of Technology (NAWI Graz), Stremayrgasse 9/Z4, 8010 Graz, Austria.
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15
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Chadwick AV, Düvel A, Heitjans P, Pickup DM, Ramos S, Sayle DC, Sayle TXT. X-Ray Absorption Spectroscopy and Computer Modelling Study of Nanocrystalline Binary Alkaline Earth Fluorides. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/1757-899x/80/1/012005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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Preishuber-Pflügl F, Bottke P, Pregartner V, Bitschnau B, Wilkening M. Correlated fluorine diffusion and ionic conduction in the nanocrystalline F(-) solid electrolyte Ba(0.6)La(0.4)F(2.4)-(19)F T1(ρ) NMR relaxation vs. conductivity measurements. Phys Chem Chem Phys 2015; 16:9580-90. [PMID: 24728404 DOI: 10.1039/c4cp00422a] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Chemical reactions induced by mechanical treatment may give access to new compounds whose properties are governed by chemical metastability, defects introduced and the size effects present. Their interplay may lead to nanocrystalline ceramics with enhanced transport properties being useful to act as solid electrolytes. Here, the introduction of large amounts of La into the cubic structure of BaF2 served as such an example. The ion transport properties in terms of dc-conductivity values of the F(-) anion conductor Ba1-xLaxF2+x (here with x = 0.4) considerably exceed those of pure, nanocrystalline BaF2. So far, there is only little knowledge about activation energies and jump rates of the elementary hopping processes. Here, we took advantage of both impedance spectroscopy and (19)F NMR relaxometry to get to the bottom of ion jump diffusion proceeding on short-range and long-range length scales in Ba0.6La0.4F2.4. While macroscopic transport is governed by an activation energy of 0.55 to 0.59 eV, the elementary steps of hopping seen by NMR are characterised by much smaller activation energies. Fortunately, we were able to deduce an F(-) self-diffusion coefficient by the application of spin-locking NMR relaxometry.
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Affiliation(s)
- F Preishuber-Pflügl
- Institute for Chemistry and Technology of Materials, and Christian Doppler Laboratory for Lithium Batteries, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria.
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17
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Mu X, Sigle W, Bach A, Fischer D, Jansen M, van Aken PA. Influence of a Second Cation (M= Ca2+, Mg2+) on the Phase Evolution of (BaxM1-x)F2Starting from Amorphous Deposits. Z Anorg Allg Chem 2014. [DOI: 10.1002/zaac.201400099] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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18
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Preishuber-Pflügl F, Wilkening M. Evidence of low dimensional ion transport in mechanosynthesized nanocrystalline BaMgF4. Dalton Trans 2014; 43:9901-8. [DOI: 10.1039/c4dt00904e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The ternary fluoride BaMgF4 is mechanically synthesized and shows anisotropic F dynamics even in its nanocrystalline form.
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Affiliation(s)
- F. Preishuber-Pflügl
- Graz University of Technology
- Institute for Chemistry and Technology of Materials (Member of NAWI Graz)
- 8010 Graz, Austria
| | - M. Wilkening
- Graz University of Technology
- Institute for Chemistry and Technology of Materials (Member of NAWI Graz)
- 8010 Graz, Austria
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19
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Zahn D, Heitjans P, Maier J. From Composites to Solid Solutions: Modeling of Ionic Conductivity in the CaF2-BaF2System. Chemistry 2012; 18:6225-9. [DOI: 10.1002/chem.201102410] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Indexed: 11/10/2022]
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20
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Düvel A, Wegner S, Efimov K, Feldhoff A, Heitjans P, Wilkening M. Access to metastable complex ion conductors via mechanosynthesis: preparation, microstructure and conductivity of (Ba,Sr)LiF3 with inverse perovskite structure. ACTA ACUST UNITED AC 2011. [DOI: 10.1039/c0jm03439h] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Düvel A, Wilkening M, Uecker R, Wegner S, Šepelák V, Heitjans P. Mechanosynthesized nanocrystalline BaLiF3: The impact of grain boundaries and structural disorder on ionic transport. Phys Chem Chem Phys 2010; 12:11251-62. [DOI: 10.1039/c004530f] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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