Solid state ionics

The Festkörperionik ( English Solid State Ionics ) is a scientific and technical field, which consists of partial areas of the solid-state physics and the electrochemistry is.

Solid-state ionics deals with solids that are electrically conductive and for which this conductivity is primarily based on the mobility of ions in the solid. These solid ion conductors are also called solid electrolytes ; therefore solid state ionics can also be referred to as the science of solid electrolytes. Solid-state ionics has important applications, for example in sensor technology and in high-temperature fuel cells ( solid oxide fuel cells ); these applications are detailed under application examples .

Basics

The electrical conductivity comes about because one type of ion is usually mobile in the solid. The ions hop from one free lattice site to the next, an activation energy E _a having to be overcome for the jump . Then the simple model gives a dependence for the conductivity σ corresponding to the Arrhenius equation, i.e. H.

${\displaystyle {\sigma =\sigma _{0}\cdot \mathrm {e} ^{-{\frac {E_{\mathrm {A} }}{R\cdot T}}}}}$

With

• ${\displaystyle \sigma }$ electrical conductivity (SI unit: S m ⁻¹ = Ω ⁻¹ m ⁻¹ )
• ${\displaystyle \sigma _{0}}$ Limit conductivity for high temperatures ( ) ${\displaystyle T\to +\infty }$
• ${\displaystyle E_{\mathrm {A} }}$ Activation energy (J mol ⁻¹ )
• ${\displaystyle R}$ universal gas constant (8.314 J K ⁻¹ mol ⁻¹ )
• ${\displaystyle T}$ absolute (thermodynamic) temperature (unit: K ).

For conductivities σ determined experimentally, the logarithms ln σ are often plotted against the reciprocal value of the temperature (1 / T ). Most of the time, the given equation is fulfilled to a good approximation and straight lines result which fall with a slope - E _a / R.

Historical

Heinrich Buff had already established in 1854 that the resistance of glass decreases with increasing temperature. In contrast to the usual behavior with metals, the conductivity of which decreases with increasing temperature, it accordingly increases with solid electrolytes with increasing temperature. In 1884 Emil Warburg showed that electrolysis of the glass takes place when a power line is conducted , which leads to a poorly conductive, low-sodium silica layer on the anode. The formation of this layer can be prevented if sodium amalgam is used on the anode side . He concluded from this that the anions of the glass remain and that only the cation, i.e. H. the sodium ion, migrating through the glass. Walther Nernst patented the first technical application of solid electrolytes in 1897, the Nernst lamp . AEG bought the patent and lit a pavilion with 800 Nernst lamps at the World Exhibition in Paris in 1900. In 1960, the Japanese Takehiko Takahashi coined the term “solid state ionics”, and the subsequent boom in solid state ionics helped establish it as a field. Since 1980, it has had its own regular publication, the “Solid State Ionics” magazine.

Solid-state ionics research

Solid-state ionics is being researched at many universities. B. in Giessen, Kiel and Marburg, in Austria z. B. in Vienna. Non-European research on solid-state ionics takes place e.g. B. in Pasadena or Sendai instead.

Individual evidence

1. ↑ Heinrich Buff: About the electrical conductivity of heated glass . In: Friedrich Wöhler, Justus Liebig, Hermann Kopp (eds.): Justus Liebig's annals of chemistry and pharmacy . 90 (new series volume 14 ), no. 3 . CF Winter, Heidelberg 1854, p. 257–283 , doi : 10.1002 / jlac.18540900302 ( online from archive.org - the Internet Archive [accessed April 10, 2015]).
2. ↑ ^{a b c} Emil Warburg: About the electrolysis of solid glass . From the reports on the negotiating the natural scientist. Society to Freiburg i. Br. Vol. 8 p. 2, communicated by the author. In: Gustav Wiedemann (Ed.): Annalen der Physik und Chemie . 257 (new episode volume 21 ), no. 4 . Johann Ambrosius Barth, Leipzig 1884, p. 622–646 , doi : 10.1002 / andp.18832570406 ( online on the pages of the Thuringian University and State Library Jena (ThULB) [PDF; accessed on March 29, 2015] online on the pages of archive.org ).
3. ↑ TransMIT center for solid state ionics and electrochemistry. TransMIT GmbH, 2015, accessed on April 7, 2015 (Prof. Dr. Jürgen Janek, Physikalisch-Chemisches Institut, Justus Liebig University Giessen). 
4. ↑ Jingping Hu: Chair for Sensor Technology and Solid State Ionic Technology. Technical Faculty of Christian Albrechts University, 2004, accessed on April 7, 2015 (Prof. Werner Weppner, Chair for Sensor Technology and Solid State Ionics, Technical Faculty, Christian Albrechts University, Kiel; now retired). 
5. ↑ Wangy: Welcome to the Roling working group. Department of Chemistry, Philipps University Marburg, October 17, 2014, accessed on 7 April 2015 (Prof. Bernhard Roling, Department of Chemistry, Physical Chemistry, Philipps University Marburg). 
6. ^ Daniela Hallegger: Jürgen Fleig - Professor of Technical Electrochemistry with a focus on solid state ionics. Vienna University of Technology, December 13, 2007, accessed on April 7, 2015 (Prof. Jürgen Fleig, Vienna University of Technology). 
7. ^ Solid State Ionics and Electroceramics Research Group. (No longer available online.) California Institute of Technology, archived from the original on April 13, 2015 ; Retrieved April 7, 2015 (Prof. Sossina M. Haile, Solid State Ionics and Electroceramics Research Group, California Institute of Technology). Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  
8. ^ Solid State Ion Physics Group. Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, accessed April 7, 2015 (Prof. Junichi Kawamura, Solid State Ion Physics Group, Tohoku University, Sendai, Japan).