Solid Electrolytes: Microstructural Characterization by Conductivity Spectroscopy

1995 ◽  
Vol 411 ◽  
Author(s):  
K. Funke

ABSTRACTIn conductivity spectroscopy, ionic conductivities of solid electrolytes are measured continuously from a few Hertz up to the mid-infrared, i.e., in a frequency range covering more than twelve decades. In this paper we present experimental conductivity spectra of various cryst alline and glassy ionic conductors. Tracing the characteristic patterns of the spectra back to their generic processes provides a powerful means for probing the motion of the ions on atomic scales of space and time. The technique is particularly useful for exploring the single-particle potentials felt by the ions and, hence, for elucidating details of the surrounding structure. In our examples we discuss widths, anisotropies, and geometrical arrangements of sites in crystals as well as the existence of non-equivalent sites in glass.

2020 ◽  
Author(s):  
Saneyuki Ohno ◽  
Tim Bernges ◽  
Johannes Buchheim ◽  
Marc Duchardt ◽  
Anna-Katharina Hatz ◽  
...  

<p>Owing to highly conductive solid ionic conductors, all-solid-state batteries attract significant attention as promising next-generation energy storage devices. A lot of research is invested in the search and optimization of solid electrolytes with higher ionic conductivity. However, a systematic study of an <i>interlaboratory reproducibility</i> of measured ionic conductivities and activation energies is missing, making the comparison of absolute values in literature challenging. In this study, we perform an uncertainty evaluation via a Round Robin approach using different Li-argyrodites exhibiting orders of magnitude different ionic conductivities as reference materials. Identical samples are distributed to different research laboratories and the conductivities and activation barriers are measured by impedance spectroscopy. The results show large ranges of up to 4.5 mScm<sup>-1</sup> in the measured total ionic conductivity (1.3 – 5.8 mScm<sup>-1</sup> for the highest conducting sample, relative standard deviation 35 – 50% across all samples) and up to 128 meV for the activation barriers (198 – 326 meV, relative standard deviation 5 – 15%, across all samples), presenting the necessity of a more rigorous methodology including further collaborations within the community and multiplicate measurements.</p>


1998 ◽  
Vol 548 ◽  
Author(s):  
K. Funke ◽  
D. Wilmer

ABSTRACTCrystalline ion conductors like RbAg4I5 and others display a characteristic shape of their dispersive conductivities at frequencies below the microwave regime. As the temperature is decreased, the onset of the dispersion is shifted to lower frequencies and thus the characteristic shape of the dispersion becomes visible in an increasingly broad frequency range. In a log-log plot of the frequency-dependent conductivity, the slope is found to increase continuously, but not to surpass unity. For the first time, this behavior is now consistently explained. The particular shape of the dispersion is shown to be equivalent to a proportionality of the rates of relaxation via the singleand many-particle routes. This is the essence of the concept of mismatch and relaxation (CMR). Model conductivity spectra based on the CMR include the UDR (universal dynamic response) as well as the NCL (nearly constant loss) behavior. Both universalities are thus traced back to a common dynamic origin.


Author(s):  
Saneyuki Ohno ◽  
Tim Bernges ◽  
Johannes Buchheim ◽  
Marc Duchardt ◽  
Anna-Katharina Hatz ◽  
...  

<p>Owing to highly conductive solid ionic conductors, all-solid-state batteries attract significant attention as promising next-generation energy storage devices. A lot of research is invested in the search and optimization of solid electrolytes with higher ionic conductivity. However, a systematic study of an <i>interlaboratory reproducibility</i> of measured ionic conductivities and activation energies is missing, making the comparison of absolute values in literature challenging. In this study, we perform an uncertainty evaluation via a Round Robin approach using different Li-argyrodites exhibiting orders of magnitude different ionic conductivities as reference materials. Identical samples are distributed to different research laboratories and the conductivities and activation barriers are measured by impedance spectroscopy. The results show large ranges of up to 4.5 mScm<sup>-1</sup> in the measured total ionic conductivity (1.3 – 5.8 mScm<sup>-1</sup> for the highest conducting sample, relative standard deviation 35 – 50% across all samples) and up to 128 meV for the activation barriers (198 – 326 meV, relative standard deviation 5 – 15%, across all samples), presenting the necessity of a more rigorous methodology including further collaborations within the community and multiplicate measurements.</p>


2020 ◽  
Author(s):  
Saneyuki Ohno ◽  
Tim Bernges ◽  
Johannes Buchheim ◽  
Marc Duchardt ◽  
Anna-Katharina Hatz ◽  
...  

<p>Owing to highly conductive solid ionic conductors, all-solid-state batteries attract significant attention as promising next-generation energy storage devices. A lot of research is invested in the search and optimization of solid electrolytes with higher ionic conductivity. However, a systematic study of an <i>interlaboratory reproducibility</i> of measured ionic conductivities and activation energies is missing, making the comparison of absolute values in literature challenging. In this study, we perform an uncertainty evaluation via a Round Robin approach using different Li-argyrodites exhibiting orders of magnitude different ionic conductivities as reference materials. Identical samples are distributed to different research laboratories and the conductivities and activation barriers are measured by impedance spectroscopy. The results show large ranges of up to 4.5 mScm<sup>-1</sup> in the measured total ionic conductivity (1.3 – 5.8 mScm<sup>-1</sup> for the highest conducting sample, relative standard deviation 35 – 50% across all samples) and up to 128 meV for the activation barriers (198 – 326 meV, relative standard deviation 5 – 15%, across all samples), presenting the necessity of a more rigorous methodology including further collaborations within the community and multiplicate measurements.</p>


Author(s):  
R. B. Queenan ◽  
P. K. Davies

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.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shenghan Gao ◽  
Thibault Broux ◽  
Susumu Fujii ◽  
Cédric Tassel ◽  
Kentaro Yamamoto ◽  
...  

AbstractMost solid-state materials are composed of p-block anions, only in recent years the introduction of hydride anions (1s2) in oxides (e.g., SrVO2H, BaTi(O,H)3) has allowed the discovery of various interesting properties. Here we exploit the large polarizability of hydride anions (H–) together with chalcogenide (Ch2–) anions to construct a family of antiperovskites with soft anionic sublattices. The M3HCh antiperovskites (M = Li, Na) adopt the ideal cubic structure except orthorhombic Na3HS, despite the large variation in sizes of M and Ch. This unconventional robustness of cubic phase mainly originates from the large size-flexibility of the H– anion. Theoretical and experimental studies reveal low migration barriers for Li+/Na+ transport and high ionic conductivity, possibly promoted by a soft phonon mode associated with the rotational motion of HM6 octahedra in their cubic forms. Aliovalent substitution to create vacancies has further enhanced ionic conductivities of this series of antiperovskites, resulting in Na2.9H(Se0.9I0.1) achieving a high conductivity of ~1 × 10–4 S/cm (100 °C).


Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 293
Author(s):  
Liangzhu Zhu ◽  
Anil V. Virkar

Na-β″-alumina (Na2O.~6Al2O3) is known to be an excellent sodium ion conductor in battery and sensor applications. In this study we report fabrication of Na- β″-alumina + YSZ dual phase composite to mitigate moisture and CO2 corrosion that otherwise can lead to degradation in pure Na-β″-alumina conductor. Subsequently, we heat-treated the samples in molten AgNO3 and LiNO3 to respectively form Ag-β″-alumina + YSZ and Li-β″-alumina + YSZ to investigate their potential applications in silver- and lithium-ion solid state batteries. Ion exchange fronts were captured via SEM and EDS techniques. Their ionic conductivities were measured using electrochemical impedance spectroscopy. Both ion exchange rates and ionic conductivities of these composite ionic conductors were firstly reported here and measured as a function of ion exchange time and temperature.


Author(s):  
Wolfgang Schmickler

Electrochemistry is an old science: There is good archaeological evidence that an electrolytic cell was used by the Parthans (250 B.C. to 250 A.D.), probably for electroplating, though a proper scientific investigation of electrochemical phenomena did not start before the experiments of Volta and Galvani. The meaning and scope of electrochemical science has varied throughout the ages: For a long time it was little more than a special branch of thermodynamics; later attention turned to electrochemical kinetics. During recent decades, with the application of various surface-sensitive techniques to electrochemical systems, it has become a science of interfaces, and this, we think, is where its future lies. So in this book we use as a working definition: . . . Electrochemistry is the study of structures and processes at the interface between an electronic conductor (the electrode) and an ionic conductor (the electrolyte) or at the interface between two electrolytes. . . This definition requires some explanation. (1) By interface we denote those regions of the two adjoining phases whose properties differ significantly from those of the bulk. These interfacial regions can be quite extended, particularly in those cases where a metal or semiconducting electrode is covered by a thin film. Sometimes the term interphase is used to indicate the spatial extention. (2) It would have been more natural to restrict the definition to the interface between an electronic and an ionic conductor only, and, indeed, this is generally what we mean by the term electrochemical interface. However, the study of the interface between two immiscible electrolyte solutions is so similar that it is natural to include it under the scope of electrochemistry. Metals and semiconductors are common examples of electronic conductors, and under certain circumstances even insulators can be made electronically conducting, for example by photoexcitation. Electrolyte solutions, molten salts, and solid electrolytes are ionic conductors. Some materials have appreciable electronic and ionic conductivities, and depending on the circumstances one or the other or both may be important.


2019 ◽  
Vol 58 (1) ◽  
pp. 248-270 ◽  
Author(s):  
Chandra Sekhar Dash ◽  
S. R. S. Prabaharan

Abstract Use of solid state ionic conductors the so-called Solid Electrolytes has brought new impetus to the field of solid state memories namely resistive random access memory (Re-RAM). In this review article, to begin we present the detailed understanding on the basics of solid electrolytes. Later, the same has been reviewed focusing on its application in novel solid state memory applications. Few examples of solid electrolytes are considered and their impact on the state-of-art research in this domain is discussed in detail. An in-depth analysis on the fundamentals of Resistive switching mechanism involved in various classes of Memristive devices viz., Electrochemical Metallization Memories (ECM) and Valence change Memories (VCM). A few important applications of Memristors such as Neuristor and artificial synapse in neuromorphic computing are reviewed as well. Finally, the most anticipated energy efficient battery-like cells as artificial synapse in brain-inspired computing is also covered.


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