A Lattice Dynamical Approach for Finding the Lithium Superionic Conductor Li3ErI6

2020 ◽  
Author(s):  
Roman Schlem ◽  
Tim Bernges ◽  
Cheng Li ◽  
Marvin Kraft ◽  
Nicolo Minafra ◽  
...  
Keyword(s):  
Lattice Dynamics ◽  
Ionic Conductivities ◽  
Ionic Transport ◽  
Superionic Conductors ◽  
Material System ◽  
Ionic Conductors ◽  
Anion Sublattice ◽  
Temperature Dependent ◽  
Solid State Batteries ◽  
Debye Frequency

<p>Driven by the increasing attention that the superionic conductors Li<sub>3</sub>MX<sub>6</sub> (M = Y, Er, In, La; X = Cl, Br, I) have gained recently for the use of solid-state batteries, and the idea that a softer, more polarizable anion sublattice is beneficial for ionic transport, here we report Li<sub>3</sub>ErI<sub>6</sub>, the first experimentally-obtained iodine-based compound within this material system of ionic conductors. Using a combination of synchrotron and neutron diffraction, we elucidate the structure, the lithium positions and possible diffusion pathways of Li<sub>3</sub>ErI<sub>6</sub>. Temperature-dependent impedance spectroscopy shows low activation energies of 0.37 and 0.38 eV alongside promising ionic conductivities of 0.65 mS·cm<sup>-1</sup> and 0.39 mS·cm<sup>-1</sup>directly after ball milling and the subsequently annealed Li<sub>3</sub>ErI<sub>6</sub>, respectively. Speed of sound measurements are used to determine the Debye frequency of the lattice as a descriptor of the lattice dynamics and overall lattice softness, and Li<sub>3</sub>ErI<sub>6</sub> is compared to the known material Li<sub>3</sub>ErCl<sub>6</sub>. The softer, more polarizable framework from the iodide anion leads to improved ionic transport, showing that the idea of softer lattices holds up in this class of materials. This work provides Li<sub>3</sub>ErI<sub>6</sub> as an interesting novel framework for optimization in the class of halide-based ionic conductors.</p>

scholarly journals A Lattice Dynamical Approach for Finding the Lithium Superionic Conductor Li3ErI6

2020 ◽  
Author(s):  
Roman Schlem ◽  
Tim Bernges ◽  
Cheng Li ◽  
Marvin Kraft ◽  
Nicolo Minafra ◽  
...  
Keyword(s):  
Lattice Dynamics ◽  
Ionic Conductivities ◽  
Ionic Transport ◽  
Superionic Conductors ◽  
Material System ◽  
Ionic Conductors ◽  
Anion Sublattice ◽  
Temperature Dependent ◽  
Solid State Batteries ◽  
Debye Frequency

<p>Driven by the increasing attention that the superionic conductors Li<sub>3</sub>MX<sub>6</sub> (M = Y, Er, In, La; X = Cl, Br, I) have gained recently for the use of solid-state batteries, and the idea that a softer, more polarizable anion sublattice is beneficial for ionic transport, here we report Li<sub>3</sub>ErI<sub>6</sub>, the first experimentally-obtained iodine-based compound within this material system of ionic conductors. Using a combination of synchrotron and neutron diffraction, we elucidate the structure, the lithium positions and possible diffusion pathways of Li<sub>3</sub>ErI<sub>6</sub>. Temperature-dependent impedance spectroscopy shows low activation energies of 0.37 and 0.38 eV alongside promising ionic conductivities of 0.65 mS·cm<sup>-1</sup> and 0.39 mS·cm<sup>-1</sup>directly after ball milling and the subsequently annealed Li<sub>3</sub>ErI<sub>6</sub>, respectively. Speed of sound measurements are used to determine the Debye frequency of the lattice as a descriptor of the lattice dynamics and overall lattice softness, and Li<sub>3</sub>ErI<sub>6</sub> is compared to the known material Li<sub>3</sub>ErCl<sub>6</sub>. The softer, more polarizable framework from the iodide anion leads to improved ionic transport, showing that the idea of softer lattices holds up in this class of materials. This work provides Li<sub>3</sub>ErI<sub>6</sub> as an interesting novel framework for optimization in the class of halide-based ionic conductors.</p>

Exploring the Influence of Substitution on the Structure and Transport Properties in the Sodium Superionic Conductor Na11+xSn2+x(Sb1−yPy)1−xS12

2020 ◽  
Author(s):  
Marvin Kraft ◽  
Lara Gronych ◽  
Theodosios Famprikis ◽  
Saneyuki Ohno ◽  
Wolfgang Zeier
Keyword(s):  
Electrochemical Impedance ◽  
Structural Phase ◽  
Ionic Transport ◽  
Sodium Ion ◽  
Ionic Conductors ◽  
Temperature Dependent ◽  
Activation Barriers ◽  
Rietveld Refinements ◽  
High Performing ◽  
The Given

<p>Sulfidic sodium ion conductors are currently investigated for the possible use in all-solid-state sodium ion batteries. The design of high performing electrolytes in terms of temperature-dependent ionic transport is based upon the fundamental understanding of structure – transport relationships within the given structural phase boundaries inherent to the investigated materials class. In this work, the Na<sup>+</sup> superionic structural family of Na<sub>11</sub>Sn<sub>2</sub>PS<sub>12</sub> is explored by using the systematic antimony substitution with phosphorous in Na<sub>11+<i>x</i></sub>Sn<sub>2+<i>x</i></sub>(Sb<sub>1-<i>y</i></sub>P<i><sub>y</sub></i>)<sub>1-<i>x</i></sub>S<sub>12</sub>. A combination of Rietveld refinements against X-ray synchrotron diffraction data with electrochemical impedance spectroscopy is used to monitor the changes in the anionic framework, the Na<sup>+</sup> substructure and the ionic transport. A new simplified descriptor for the average Na<sup>+</sup> diffusion pathways, the average Na<sup>+</sup> polyhedral volume is introduced, which is used to correlate the contraction of the overall lattice and the found activation barriers in the system. This study exemplifies how substitution affects diffusion pathways in ionic conductors and widens the knowledge about the related structural motifs and their influence on the ionic transport in this novel class of ionic conductors.</p>

Rapid Crystallization and Kinetic Freezing of Site-Disorder in the Lithium Superionic Argyrodite Li6PS5Br

2019 ◽  
Author(s):  
Ajay Gautam ◽  
Marcel Sadowski ◽  
Nils Prinz ◽  
Henrik Eickhoff ◽  
Nicolo Minafra ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Synthesis Method ◽  
Reaction Times ◽  
Ionic Conductivities ◽  
Ionic Transport ◽  
High Energy ◽  
Superionic Conductors ◽  
Rapid Crystallization ◽  
Site Disorder ◽  
Fast Cooling

<p>Lithium argyrodite superionic conductors are currently being investigated as solid electrolytes for all-solid-state batteries. Recently, in the lithium argyrodite Li<sub>6</sub>PS<sub>5</sub>X (X = Cl, Br, I), a site-disorder between the anionsS<sup>2–</sup>and X<sup>–</sup>has been observed, which strongly affects the ionic transport and appears to be a function of the halide present. In this work, we show how such disorder in Li<sub>6</sub>PS<sub>5</sub>Br can be engineered <i>via</i>the synthesis method. By comparing fast cooling (<i>i.e. </i>quenching) to more slowly cooled samples, we find that anion site-disorder is higher at elevated temperatures, and that fast cooling can be used to kinetically trap the desired disorder, leading to higher ionic conductivities as shown by impedance spectroscopy in combination with <i>ab-initio</i>molecular dynamics. Furthermore, we observe that after milling, a crystalline lithium argyrodite can be obtained within one minute of heat treatment. This rapid crystallization highlights the reactive nature of mechanical milling and shows that long reaction times with high energy consumption are not needed in this class of materials. The fact that site-disorder induced <i>via</i>quenching is beneficial for ionic transport provides an additional approach for the optimization and design of lithium superionic conductors.</p>

scholarly journals Rapid Crystallization and Kinetic Freezing of Site-Disorder in the Lithium Superionic Argyrodite Li6PS5Br

2019 ◽  
Author(s):  
Ajay Gautam ◽  
Marcel Sadowski ◽  
Nils Prinz ◽  
Henrik Eickhoff ◽  
Nicolo Minafra ◽  
...  
Keyword(s):  
Elevated Temperatures ◽  
Synthesis Method ◽  
Reaction Times ◽  
Ionic Conductivities ◽  
Ionic Transport ◽  
High Energy ◽  
Superionic Conductors ◽  
Rapid Crystallization ◽  
Site Disorder ◽  
Fast Cooling

<p>Lithium argyrodite superionic conductors are currently being investigated as solid electrolytes for all-solid-state batteries. Recently, in the lithium argyrodite Li<sub>6</sub>PS<sub>5</sub>X (X = Cl, Br, I), a site-disorder between the anionsS<sup>2–</sup>and X<sup>–</sup>has been observed, which strongly affects the ionic transport and appears to be a function of the halide present. In this work, we show how such disorder in Li<sub>6</sub>PS<sub>5</sub>Br can be engineered <i>via</i>the synthesis method. By comparing fast cooling (<i>i.e. </i>quenching) to more slowly cooled samples, we find that anion site-disorder is higher at elevated temperatures, and that fast cooling can be used to kinetically trap the desired disorder, leading to higher ionic conductivities as shown by impedance spectroscopy in combination with <i>ab-initio</i>molecular dynamics. Furthermore, we observe that after milling, a crystalline lithium argyrodite can be obtained within one minute of heat treatment. This rapid crystallization highlights the reactive nature of mechanical milling and shows that long reaction times with high energy consumption are not needed in this class of materials. The fact that site-disorder induced <i>via</i>quenching is beneficial for ionic transport provides an additional approach for the optimization and design of lithium superionic conductors.</p>

Exploring the Influence of Substitution on the Structure and Transport Properties in the Sodium Superionic Conductor Na11+xSn2+x(Sb1−yPy)1−xS12

2020 ◽  
Author(s):  
Marvin Kraft ◽  
Lara Gronych ◽  
Theodosios Famprikis ◽  
Saneyuki Ohno ◽  
Wolfgang Zeier
Keyword(s):  
Electrochemical Impedance ◽  
Structural Phase ◽  
Ionic Transport ◽  
Sodium Ion ◽  
Ionic Conductors ◽  
Temperature Dependent ◽  
Activation Barriers ◽  
Rietveld Refinements ◽  
High Performing ◽  
The Given

<p>Sulfidic sodium ion conductors are currently investigated for the possible use in all-solid-state sodium ion batteries. The design of high performing electrolytes in terms of temperature-dependent ionic transport is based upon the fundamental understanding of structure – transport relationships within the given structural phase boundaries inherent to the investigated materials class. In this work, the Na<sup>+</sup> superionic structural family of Na<sub>11</sub>Sn<sub>2</sub>PS<sub>12</sub> is explored by using the systematic antimony substitution with phosphorous in Na<sub>11+<i>x</i></sub>Sn<sub>2+<i>x</i></sub>(Sb<sub>1-<i>y</i></sub>P<i><sub>y</sub></i>)<sub>1-<i>x</i></sub>S<sub>12</sub>. A combination of Rietveld refinements against X-ray synchrotron diffraction data with electrochemical impedance spectroscopy is used to monitor the changes in the anionic framework, the Na<sup>+</sup> substructure and the ionic transport. A new simplified descriptor for the average Na<sup>+</sup> diffusion pathways, the average Na<sup>+</sup> polyhedral volume is introduced, which is used to correlate the contraction of the overall lattice and the found activation barriers in the system. This study exemplifies how substitution affects diffusion pathways in ionic conductors and widens the knowledge about the related structural motifs and their influence on the ionic transport in this novel class of ionic conductors.</p>

scholarly journals Diffuson-mediated thermal and ionic transport in superionic conductors

2021 ◽  
Author(s):  
Tim Bernges ◽  
Riley Hanus ◽  
Bjoern Wankmiller ◽  
Kazuki Imasato ◽  
Siqi Lin ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Solid State ◽  
Thermal Transport ◽  
Ionic Conductivities ◽  
Ionic Transport ◽  
Superionic Conductors ◽  
Design Strategies ◽  
Dynamics Modeling ◽  
Physical Relationship ◽  
Low Thermal Conductivity

Ultra-low lattice thermal conductivity as often found in superionic compounds is greatly beneficial for thermoelectric performance, however, a high ionic conductivity can lead to device degradation. Conversely, high ionic conductivities are searched for materials in solid-state battery applications. It is commonly thought that ionic transport induces low thermal conductivity and that ion and thermal transport are not completely independent properties of a material. However, no direct comparison or underlying physical relationship has been shown between the two. Here we establish that ionic transport can be varied independent of thermal transport in Ag+ superionic conductors, even though both phenomena arise from atomic vibrations. Thermal conductivity measurements, in conjunction with two-channel lattice dynamics modeling, reveals that the vast majority of Ag+ vibrations have non-propagating diffuson-like character, which provides a rational for how these two transport properties can be independent. Our results provide conceptually novel lattice dynamical insights to ionic transport and confirm that ion transport is not a requirement for ultra-low thermal conductivity. Consequently, this work bridges the fields of solid state ionics and thermal transport, thus providing design strategies for functional ionic conducting materials from a vibrational perspective.

Exploring the Influence of Substitution on the Structure and Transport Properties in the Sodium Superionic Conductor Na11+xSn2+x(Sb1−yPy)1−xS12

2020 ◽  
Author(s):  
Marvin Kraft ◽  
Lara Gronych ◽  
Theodosios Famprikis ◽  
Saneyuki Ohno ◽  
Wolfgang Zeier
Keyword(s):  
Electrochemical Impedance ◽  
Structural Phase ◽  
Ionic Transport ◽  
Sodium Ion ◽  
Ionic Conductors ◽  
Temperature Dependent ◽  
Activation Barriers ◽  
Rietveld Refinements ◽  
High Performing ◽  
The Given

<p>Sulfidic sodium ion conductors are currently investigated for the possible use in all-solid-state sodium ion batteries. The design of high performing electrolytes in terms of temperature-dependent ionic transport is based upon the fundamental understanding of structure – transport relationships within the given structural phase boundaries inherent to the investigated materials class. In this work, the Na<sup>+</sup> superionic structural family of Na<sub>11</sub>Sn<sub>2</sub>PS<sub>12</sub> is explored by using the systematic antimony substitution with phosphorous in Na<sub>11+<i>x</i></sub>Sn<sub>2+<i>x</i></sub>(Sb<sub>1-<i>y</i></sub>P<i><sub>y</sub></i>)<sub>1-<i>x</i></sub>S<sub>12</sub>. A combination of Rietveld refinements against X-ray synchrotron diffraction data with electrochemical impedance spectroscopy is used to monitor the changes in the anionic framework, the Na<sup>+</sup> substructure and the ionic transport. A new simplified descriptor for the average Na<sup>+</sup> diffusion pathways, the average Na<sup>+</sup> polyhedral volume is introduced, which is used to correlate the contraction of the overall lattice and the found activation barriers in the system. This study exemplifies how substitution affects diffusion pathways in ionic conductors and widens the knowledge about the related structural motifs and their influence on the ionic transport in this novel class of ionic conductors.</p>

scholarly journals On the underestimated influence of synthetic conditions in solid ionic conductors

2021 ◽  
Author(s):  
Ananya Banik ◽  
Theodosios Famprikis ◽  
Michael Ghidiu ◽  
Saneyuki Ohno ◽  
Marvin A. Kraft ◽  
...  
Keyword(s):  
Transport Properties ◽  
Ionic Transport ◽  
Superionic Conductors ◽  
Ionic Conductors ◽  
Synthesis And Processing

Influence of synthesis and processing on the nature of ultimate product and the ionic transport properties of superionic conductors.

A transmission electron microscopic study of structural transitions in fast ionic conductors

1987 ◽  
Vol 45 ◽  
pp. 156-157
Author(s):  
R. B. Queenan ◽  
P. K. Davies
Keyword(s):  
Optical Properties ◽  
Ionic Conduction ◽  
Recent Observation ◽  
Ionic Conductivities ◽  
Sodium Aluminate ◽  
Two Dimensions ◽  
Ionic Conductors ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Trivalent Cations

Na ß“-alumina (Na1.67Mg67Al10.33O17) is a non-stoichiometric sodium aluminate which exhibits fast ionic conduction of the Na+ ions in two dimensions. The Na+ ions can be exchanged with a variety of mono-, di-, and trivalent cations. The resulting exchanged materials also show high ionic conductivities.Considerable interest in the Na+-Nd3+-ß“-aluminas has been generated as a result of the recent observation of lasing in the pulsed and cw modes. A recent TEM investigation on a 100% exchanged Nd ß“-alumina sample found evidence for the intergrowth of two different structure types. Microdiffraction revealed an ordered phase coexisting with an apparently disordered phase, in which the cations are completely randomized in two dimensions. If an order-disorder transition is present then the cooling rates would be expected to affect the microstructures of these materials which may in turn affect the optical properties. The purpose of this work was to investigate the affect of thermal treatments upon the micro-structural and optical properties of these materials.

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