Approximability of Impedance Spectra By RC Elements and Implications for Impedance Analysis

2016 ◽  
Keyword(s):  
Impedance Analysis ◽  
Impedance Spectra

Impedance Analysis of Layer Structured NBT–CBT Mixed Ceramics

1998 ◽  
Vol 12 (11) ◽  
pp. 433-441 ◽  
Author(s):  
P. S. Rama Sastry ◽  
T. Bhimasankaram ◽  
G. S. Kumar ◽  
G. Prasad
Keyword(s):  
Comparative Study ◽  
Complex Impedance ◽  
Impedance Analysis ◽  
Equivalent Circuits ◽  
Impedance Spectra ◽  
Ceramic System ◽  
Different Temperatures ◽  
Mixed Ceramics ◽  
Mixed Ceramic ◽  
Complex Impedance Spectra

Complex impedance spectra of ferroelectric mixed ceramic system ( Na 0.5 Bi 0.5)1-x Ca x Bi 4 Ti 4 O 15 with x=0, 0.1, 0.3, 0.5, 0.7 and 1 was studied as a function of frequency and temperature in the range 1 KHz to 10 MHz and 30°C to 620°C respectively. Equivalent circuits involving resistive and capacitive elements at different temperatures, activation energies of relaxations and conduction were evaluated using impedance plots. A comparative study of impedance and conductivity facilities an insight in understanding the electrical nature of these electroceramics.

scholarly journals An Impedance Study of the Membrane Polarisation Effect in Simulated Rock Systems

2021 ◽  
Author(s):  
◽  
Michael Charles Harold McKubre
Keyword(s):  
Low Frequency ◽  
Impedance Measurement ◽  
Impedance Analysis ◽  
Laboratory Model ◽  
Pore Geometry ◽  
Impedance Spectra ◽  
Clay Rock ◽  
Polarisation Effect ◽  
Diffusional Limitation ◽  
Electrochemical Model

<p>Work is reported on the development of a high precision, low frequency impedance bridge, and the use of impedance measurement in characterising the induced polarisation effect of unmineralised material. Impedance spectra for a variety of laboratory model clay/rock/electrolyte systems are analysed in terms of an equivalent circuit. By measuring the dependence of the parameters of this circuit, on such variables as electrolyte type and concentration, temperature and pore geometry, an electrochemical model for membrane polarisation has been developed. Polarisation is considered to arise from diffusional limitation of cations at the membrane/electrolyte interface of clay aggregations in rock pores, and this is found to be amenable to a Warburg diffusional impedance analysis.</p>

Impedance analysis of porous electrode structures in batteries and fuel cells

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
André Weber
Keyword(s):  
Fuel Cells ◽  
Porous Electrode ◽  
Relaxation Times ◽  
Lithium Ion ◽  
Impedance Analysis ◽  
Wide Frequency Range ◽  
Impedance Spectra ◽  
Transmission Line Model ◽  
Error Sources ◽  
Lithium Ion Cells

AbstractToday technical electrodes in batteries and fuel cells rely on complex multiphase microstructures that facilitate electronic, ionic and, in case of fuel cells, diffusive gas transport to the active reaction sites distributed in the electrode volume. The impedance of such electrodes can be described by the well-established transmission line model (TLM) approach. In a TLM, transport, charge transfer phenomena and capacitive effects are coupled considering microstructural features of the electrode. Its application for impedance data analysis of technical cells is challenging as the TLM impedance extends over a wide frequency range and quite often a strong overlapping with other contributions takes place.In this paper the application of the distribution of relaxation times (DRT) to the analysis of technical electrodes in batteries and fuel cells is elucidated. Different examples how to apply the DRT to analyze impedance spectra of solid oxide-, polymer electrolyte- and lithium ion-cells will be discussed. It will be shown that the TLM is usually represented by multiple peaks in the DRT, which might be strongly affected if contributions of different electrode layers overlap in the spectra. Related error sources and countermeasures are illustrated. Approaches how the DRT can be applied for the analysis of measured spectra and how it is able to support CNLS-fitting are presented.

scholarly journals A LabVIEW-based electrical bioimpedance spectroscopic data interpreter (LEBISDI) for biological tissue impedance analysis and equivalent circuit modelling

2019 ◽  
Vol 7 (1) ◽  
pp. 35-54 ◽  
Author(s):  
Tushar Kanti Bera ◽  
Nagaraju Jampana ◽  
Gilles Lubineau
Keyword(s):  
Electrical Impedance ◽  
Tissue Characterization ◽  
Impedance Analysis ◽  
Biological Tissues ◽  
Impedance Spectra ◽  
Circuit Element ◽  
Tissue Impedance ◽  
Wide Range ◽  
Electrical Bioimpedance ◽  
Impedance Parameters

Abstract Under an alternating electrical signal, biological tissues produce a complex electrical bioimpedance that is a function of tissue composition and applied signal frequencies. By studying the bioimpedance spectra of biological tissues over a wide range of frequencies, we can noninvasively probe the physiological properties of these tissues to detect possible pathological conditions. Electrical impedance spectroscopy (EIS) can provide the spectra that are needed to calculate impedance parameters within a wide range of frequencies. Before impedance parameters can be calculated and tissue information extracted, impedance spectra should be processed and analyzed by a dedicated software program. National Instruments (NI) Inc. offers LabVIEW, a fast, portable, robust, user-friendly platform for designing data-analyzing software. We developed a LabVIEW-based electrical bioimpedance spectroscopic data interpreter (LEBISDI) to analyze the electrical impedance spectra for tissue characterization in medical, biomedical and biological applications. Here, we test, calibrate and evaluate the performance of LEBISDI on the impedance data obtained from simulation studies as well as the practical EIS experimentations conducted on electronic circuit element combinations and the biological tissue samples. We analyze the Nyquist plots obtained from the EIS measurements and compare the equivalent circuit parameters calculated by LEBISDI with the corresponding original circuit parameters to assess the accuracy of the program developed. Calibration studies show that LEBISDI not only interpreted the simulated and circuit-element data accurately, but also successfully interpreted tissues impedance data and estimated the capacitive and resistive components produced by the compositions biological cells. Finally, LEBISDI efficiently calculated and analyzed variation in bioimpedance parameters of different tissue compositions, health and temperatures. LEBISDI can also be used for human tissue impedance analysis for electrical impedance-based tissue characterization, health analysis and disease diagnosis.

scholarly journals An Impedance Study of the Membrane Polarisation Effect in Simulated Rock Systems

2021 ◽  
Author(s):  
◽  
Michael Charles Harold McKubre
Keyword(s):  
Low Frequency ◽  
Impedance Measurement ◽  
Impedance Analysis ◽  
Laboratory Model ◽  
Pore Geometry ◽  
Impedance Spectra ◽  
Clay Rock ◽  
Polarisation Effect ◽  
Diffusional Limitation ◽  
Electrochemical Model

<p>Work is reported on the development of a high precision, low frequency impedance bridge, and the use of impedance measurement in characterising the induced polarisation effect of unmineralised material. Impedance spectra for a variety of laboratory model clay/rock/electrolyte systems are analysed in terms of an equivalent circuit. By measuring the dependence of the parameters of this circuit, on such variables as electrolyte type and concentration, temperature and pore geometry, an electrochemical model for membrane polarisation has been developed. Polarisation is considered to arise from diffusional limitation of cations at the membrane/electrolyte interface of clay aggregations in rock pores, and this is found to be amenable to a Warburg diffusional impedance analysis.</p>

Impedance of an Oxygen Reducing Gas-Diffusion Electrode

1984 ◽  
Vol 39 (2) ◽  
pp. 157-162 ◽  
Author(s):  
Dietrich Wabner ◽  
Rudolf Holze ◽  
Peter Schmittinger
Keyword(s):  
Diffusion Processes ◽  
Impedance Analysis ◽  
Electrode Reaction ◽  
Gas Diffusion ◽  
Porous Electrodes ◽  
Least Square ◽  
Impedance Spectra ◽  
Least Square Fit ◽  
Measured Impedance ◽  
Small Charge

The impedance of teflon bonded electrodes was measured in the frequency domain. These electrodes based on activated carbon as electrocatalyst were developed for fuel cell applications. When feeding the electrode with air or oxygen the impedance spectra could be explained by two Nernst diffusion processes and a small charge transfer process.Two methods for separating the measured impedance into partial impedances related to different steps of the electrode reaction are presented. A least square fit procedure is described which has been applied successfully to the impedance analysis of porous electrodes

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