Naslov
Solid state impedance spectroscopy: powerful analytical tool in material science

Autori
Pavić, Luka

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstract of TMU International Symposium on the Materials Science and the Characterization of Radiochemical Methods / Kubuki, S. - Lahti, 2023, 4-4

Skup
TMU Internation Symposium on the Materials Science and the Characterization of Radiochemical Methods

Mjesto i datum
Tokyo, Japan, 08.03.2023. - 09.03.2023

Vrsta sudjelovanja
Pozvano predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Solid state impedance spectroscopy ; electrical conductivity ; phosphate-based glass-(ceramics) ; transition metal oxides

Sažetak
Solid state impedance spectroscopy (SS-IS) is a powerful, non-destructive, fast and easy-to-implement technique for studying electrical and dielectric properties of diverse materials. The technique is based on excitation of the system under study by applying known voltage at different frequencies and measuring resulting current, its amplitude and phase shift. By changing the excitation frequency, the impedance of the system is obtained over a wide range of frequencies, typically from 10–2 Hz to 106 Hz, so-called impedance spectrum. The overall electrical response of the material-electrode system is the result of various frequency-dependent microscopic processes that take place in the material itself (ion and/or electron transport, polarization) and at the interface between the electrode and the material (e.g. the transition of charge carriers through the electrode or their accumulation depending on the type of electrode). Therefore, materials studied by IS may vary from ionic and mixed ionic-electronic conductors and semiconductors to dielectrics and insulators. This presentation will demonstrate methods of measuring IS of various materials under different conditions through examples of practical research. Moreover, different approaches to evaluating measured data using different formalisms (impedance, electrical conductivity, dielectric permittivity, electrical modulus) and an equivalent circuit modelling to fit impedance will be discussed. The examples of monitoring kinetic processes (phase transformation, polymerization, crystallization) using this method will be presented as well. Furthermore, special attention will be paid to solid-state materials with an emphasis on phosphate-based glass-(ceramics) systems with different conduction mechanisms: (i) mixed ion-polaron conductive glasses [1–6], (ii) mixed glass-network former glasses [7–10], (iii) mixed-conductive-mixed-glass-former-systems and (iv) glass-ceramics [11–14]. Mixed ion-polaron conductivity is present in glasses containing both mobile alkali ions and transition metal oxides (TMOs). The addition of TMOs such as WO3, Nb2O5, V2O5, and MoO3 can contribute to overall electrical conductivity in two ways, by inducing structural changes that lead to faster ionic transport and/or by small polaron hopping mechanism arising from the presence of TM ions in more than one valence state. Furthermore, mixed glass-network former effect is observed in ionically conductive glasses with two network former oxides, from conventional one (B2O3, P2O5, GeO2) to conditional one (Nb2O5, WO3, MoO3). In such systems, local structure plays an important role and it becomes even more important when glass-ceramic material is concerned. Applications of glass-(ceramic) conducting materials are expanding and they have attracted attention as potential materials for solid-state battery electrodes/electrolytes. To make a step further and expand the insights into the electrical transport of such complex materials, we use IS in combination with structural-thermal characterization. The analysis of DC conductivity gives information on the long-range transport of charge carriers, while the frequency-dependent conductivity studied by model-(free) approach gives insights into the behaviour of their localized motions in investigated materials.

Izvorni jezik
Engleski

Znanstvena područja
Fizika, Kemija

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