Approximability of impedance spectra by RC elements and implications for impedance analysis

Schönleber, Michael; Ivers-Tiffée, Ellen

doi:10.1016/j.elecom.2015.05.018

Cited by 106 publications

(40 citation statements)

References 11 publications

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“…In the right part of the figure, the calculated residuals of the spectra in regard to the Kramers-Kronig criteria is shown. the values are calculated using the LinKK software tool, developed by Karlsruhe Institute of Technology [36][37][38]. These are consistently very low and thus indicate valid impedance spectra in compliance with the linearity and time invariance (LTI) criteria.…”

Section: Experiments Ht1mentioning

confidence: 99%

In-Operando Impedance Spectroscopy and Ultrasonic Measurements during High-Temperature Abuse Experiments on Lithium-Ion Batteries

et al. 2020

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Lithium-Ion batteries are used in ever more demanding applications regarding operating range and safety requirements. This work presents a series of high-temperature abuse experiments on a nickel-manganese-cobalt oxide (NMC)/graphite lithium-ion battery cell, using advanced in-operando measurement techniques like fast impedance spectroscopy and ultrasonic waves, as well as strain-gauges. the presented results show, that by using these methods degradation effects at elevated temperature can be observed in real-time. These methods have the potential to be integrated into a battery management system in the future. Therefore they make it possible to achieve higher battery safety even under the most demanding operating conditions.

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Section: Experiments Ht1mentioning

confidence: 99%

In-Operando Impedance Spectroscopy and Ultrasonic Measurements during High-Temperature Abuse Experiments on Lithium-Ion Batteries

et al. 2020

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“…A comparison of the literature 60,62,63 (see chapter 3.4.3) and experimental data confirms the strong temperature dependency. Furthermore, comparing the process related frequencies allows for an adjustment of the related equivalent circuit model ( 72,73 (already indicating a strong overlap of both elements), whereas the experimental data only describes one signal at frequencies of 10-100 Hz. Due to the asymmetrical nature of the signal related to process (III) as well as frequencies ranging between the literature values, one can assume a far more complex physicochemical behavior than the one that can possibly be separated with the DRT-method.…”

Section: Electrochemical In-operando Analysis Of Ascs: Drt-analysis Amentioning

confidence: 99%

Chrome Poisoning of Non-Manganiferous Cathode Materials in Solid Oxide Fuel Cells (SOFCs)

Schiemann,

Vibhu,

Yildiz

et al. 2017

Meet. Abstr.

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Chrome poisoning is considered to be one of the main degradation issues of SOFC cathode materials and thus a major cause for decreased SOFC component performances in combination with a reduced durability [1, 2]. For this reason, deeper understanding of the related chrome degradation mechanisms is of fundamental interest. Since (La,Sr)(Co,Fe)O3 based cathodes show both, a good electronic and sufficient ionic conductivity, these materials are considered to be less susceptible towards chrome poisoning than pure electronic conductors such as (La,Sr)MnO3. Nevertheless, recent performed long-term stack tests showed similar poisoning effects for LSCF materials as seen for LSM cathodes, urging us to perform another in-depth analysis of the mechanisms of chrome poisoning in non-manganiferous cathode materials [3]. LSCF materials with different stoichiometry's (variable cobalt and iron contents) have been synthesized and analyzed regarding their phase purity and microstructure. Anode supported SOFCs were manufactured with these LSCF compositions and characterized by electrochemical measuring techniques (DC/AC measurements). Here, we mainly focus on impedance spectroscopy in a broad range of different operating conditions (e.g. temperature, current density, and humidity on the air side) in presence and absence of a suitable chromium source. Electrochemical impedance measurements performed at 900 °C and a cell voltage of 0.7 V in dry and humid air conditions (Figure 1) reveal that besides an initial formation step (I in Fig. 1) the ohmic and polarization resistances only show small deviations in absence of a chrome source (Rohm: dry ~ 0.125 Ω*cm², humid 0.127 - 0.130 Ω*cm²; Rpol: dry ~ 0.045 Ω*cm², humid 0.047 Ω*cm²; see Fig. 1). During a step-wise increase of current density, i.e. cathode polarization, over 48 hour periods both Rohm and Rpol remained stable (see Fig. 1). Besides the above mentioned 4-point measurements on full cells, 3-point measurements with a reference electrode were performed on symmetrical electrolyte supported half cells. By this means contributions from the Ni/YSZ anode to the overall cell impedance can be excluded and the individual cathode contributions investigated in more detail. In combination, both measuring setups should enable detailed information about the individual resistance contributions of the synthesized cathode materials with respect to the operating conditions. References [1]B. Wei, K. Chen, C.C. Wang, Z. Lüa, S.P. Jiang; “Cr deposition on porous La0.6Sr0.4Co0.2Fe0.8O3−δ electrodes of solid oxide cells under open circuit condition”; Solid State Ionics 281 (2015) 29–37 [2]L.G.J. de Haart, J. Mougin, O. Posdziech, J. Kiviaho, N.H. Menzler; “Stack Degradation in Dependence of Operation Parameters; the Real-SOFC Sensitivity Analysis”; FUEL CELLS 9 (6) (2009) 794–804 [3] N.H. Menzler, D. Sebold, Q. Fang; “Chromium-Related Degradation of Thin-Film Electrolyte SolidOxide Fuel Cell Stacks”; Journal of the Electrochemical Society, 162 (12) (2015) F1275-F1281 Figure 1

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“…As most spectra can be described by their DRT, 29) the DRT is a valid ECM but not a valid physicochemical model. The individual resistance values and time constants representing a DRT cannot be directly related to physicochemical processes in the cell.…”

Section: Drt-analysis Of Fuel Cells and Batteriesmentioning

confidence: 99%

“…As shown in 29) and 48) the DRT includes a comprehensive representation of the dynamics of the analyzed system. Thus a DRT-based model is applicable to predict the dynamic behavior of the system, as long as nonlinear effects are negligible.…”

Section: The Drt In Black Box Modelsmentioning

confidence: 99%

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Evaluation of electrochemical impedance spectra by the distribution of relaxation times

Ivers‐Tiffée

Weber

2017

J. Ceram. Soc. Japan

225

109

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Electrochemical impedance spectroscopy is a well suited method for studying the properties of electrochemical systems. In recent decades electrochemical systems were investigated at different scales, from small model electrodes to high power devices, such as fuel cells and batteries. In the latter case, the measurement of reliable spectra and their evaluation is challenging because (i) the impedance is usually very low (1 ³), (ii) there is more than one rate limiting, electrochemical process per electrode, (iii) their charge transfer and transport processes are coupled and (iv) cathodic and anodic contributions overlap in the frequency domain. The Distribution of Relaxation Times (DRT) is supportive when deconvoluting complex impedance spectra, and has therefore gained increased attention. In this paper we introduce selected results of advanced impedance analysis. We discuss the impact of impedance data quality, statistically distributed noise and single errors in the spectra. Furthermore, the applicability of DRT for establishing adequate equivalent circuit models for ceramic electrochemical devices, such as batteries and fuel cells will be discussed.

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Approximability of impedance spectra by RC elements and implications for impedance analysis

Cited by 106 publications

References 11 publications

In-Operando Impedance Spectroscopy and Ultrasonic Measurements during High-Temperature Abuse Experiments on Lithium-Ion Batteries

In-Operando Impedance Spectroscopy and Ultrasonic Measurements during High-Temperature Abuse Experiments on Lithium-Ion Batteries

Chrome Poisoning of Non-Manganiferous Cathode Materials in Solid Oxide Fuel Cells (SOFCs)

Evaluation of electrochemical impedance spectra by the distribution of relaxation times

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