Gitterdynamiken in ionischen Leitern
Zusammenfassung der Projektergebnisse
Solid ionic conductors are a class of functional materials that are currently being discussed as a possible replacement of liquid electrolytes in lithium-ion batteries. While a variety of approaches to increase ionic transport are known and understood well, the influence of a dynamic lattice has so far not been explored systematically. In other words, it is unclear how much lattice vibration and overall lattice softness/polarizability affect the ionic transport and interactions of the mobile cation species with the surrounding lattice. In this project, the hypothesis that a softer more polarizable anion sublattice lowers the activation barrier for ionic transport was investigated. A variety of different materials combinations, such as Li6PS5X with solid solutions from Cl to I via Br, Na3PS4-xSex, Li6PS5-xSexBr, Li10Ge1-xSnxPS12, Na11Sn2.1P0.9(S/Se)12, and Li6PS5-xSexI have been probed for their lattice dynamics, and have led to a broad variety of publications (16 in total). Within the project it was possible to show that indeed a synthetically induced softening of the anion lattice, by introducing softer and polarizable anions, leads to a decrease of the energy barrier that needs to be overcome for the ion to jump from one site to another. However, as a surprise, this does not necessarily lead to better ionic conductivity as the softening of the lattice affects other factors such as the jump frequency and entropy of migration. The lattice vibrations seem to link the activation barriers with the so-called Arrhenius pre-factor. Furthermore, a collaborative study showed that the lithium phonon band center can be used as a metric for finding superionic conductors. Halide-based material systems such as Li3ErCl6, Li3YCl6 and Li3ErI6 were investigated more in-depth in further publications. The results have led to a variety of questions and continuing projects such as (1) how can the Meyer-Neldel rule be overcome? (2) How much does the anharmonicity of lattice vibrations affect the entropy of migration? and (3) How do the phonons affect the ion transport and which phonons in particular? All these questions are currently be approached in projects within the group.
Projektbezogene Publikationen (Auswahl)
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Influence of Lattice Dynamics on Na+Transport in the Solid Electrolyte Na3PS4–xSex. Chemistry of Materials, 29(20), 8859-8869.
Krauskopf, Thorben; Pompe, Constantin; Kraft, Marvin A. & Zeier, Wolfgang G.
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Influence of Lattice Polarizability on the Ionic Conductivity in the Lithium Superionic Argyrodites Li6PS5X (X = Cl, Br, I). Journal of the American Chemical Society, 139(31), 10909-10918.
Kraft, Marvin A.; Culver, Sean P.; Calderon, Mario; Böcher, Felix; Krauskopf, Thorben; Senyshyn, Anatoliy; Dietrich, Christian; Zevalkink, Alexandra; Janek, Jürgen & Zeier, Wolfgang G.
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Comparing the Descriptors for Investigating the Influence of Lattice Dynamics on Ionic Transport Using the Superionic Conductor Na3PS4–xSex. Journal of the American Chemical Society, 140(43), 14464-14473.
Krauskopf, Thorben; Muy, Sokseiha; Culver, Sean P.; Ohno, Saneyuki; Delaire, Olivier; Shao-Horn, Yang & Zeier, Wolfgang G.
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Competing Structural Influences in the Li Superionic Conducting Argyrodites Li6PS5–xSexBr (0 ≤ x ≤ 1) upon Se Substitution. Inorganic Chemistry, 57(21), 13920-13928.
Bernges, Tim; Culver, Sean P.; Minafra, Nicolò; Koerver, Raimund & Zeier, Wolfgang G.
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Inducing High Ionic Conductivity in the Lithium Superionic Argyrodites Li6+xP1–xGexS5I for All-Solid-State Batteries. Journal of the American Chemical Society, 140(47), 16330-16339.
Kraft, Marvin A.; Ohno, Saneyuki; Zinkevich, Tatiana; Koerver, Raimund; Culver, Sean P.; Fuchs, Till; Senyshyn, Anatoliy; Indris, Sylvio; Morgan, Benjamin J. & Zeier, Wolfgang G.
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High-Throughput Screening of Solid-State Li-Ion Conductors Using Lattice-Dynamics Descriptors. iScience, 16, 270-282.
Muy, Sokseiha; Voss, Johannes; Schlem, Roman; Koerver, Raimund; Sedlmaier, Stefan J.; Maglia, Filippo; Lamp, Peter; Zeier, Wolfgang G. & Shao-Horn, Yang
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Mechanochemical Synthesis: A Tool to Tune Cation Site Disorder and Ionic Transport Properties of Li3MCl6 (M = Y, Er) Superionic Conductors. Advanced Energy Materials, 10(6).
Schlem, Roman; Muy, Sokseiha; Prinz, Nils; Banik, Ananya; Shao‐Horn, Yang; Zobel, Mirijam & Zeier, Wolfgang G.
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Lattice Dynamical Approach for Finding the Lithium Superionic Conductor Li3ErI6. ACS Applied Energy Materials, 3(4), 3684-3691.
Schlem, Roman; Bernges, Tim; Li, Cheng; Kraft, Marvin A.; Minafra, Nicolo & Zeier, Wolfgang G.
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Phonon–Ion Interactions: Designing Ion Mobility Based on Lattice Dynamics. Advanced Energy Materials, 11(15).
Muy, Sokseiha; Schlem, Roman; Shao‐Horn, Yang & Zeier, Wolfgang G.
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Two-Dimensional Substitution: Toward a Better Understanding of the Structure–Transport Correlations in the Li-Superionic Thio-LISICONs. Chemistry of Materials, 33(2), 727-740.
Minafra, Nicolò; Hogrefe, Katharina; Barbon, Federico; Helm, Bianca; Li, Cheng; Wilkening, H. Martin R. & Zeier, Wolfgang G.
