scholarly journals A Multi-Channel Fast Impedance Spectroscopy Instrument Developed for Quality Assurance of Super-Capacitors

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1139
Author(s):  
Farhan Farooq ◽  
Asad Khan ◽  
Seung June Lee ◽  
Mohammad Mahad Nadeem ◽  
Woojin Choi
Keyword(s):  
Quality Assurance ◽  
Impedance Spectroscopy ◽  
Mass Production ◽  
Electrochemical Impedance ◽  
Equivalent Circuit Model ◽  
Equivalent Series Resistance ◽  
Long Time ◽  
Sweeping Method ◽  
Parameter Values ◽  
Super Capacitors

Conventional experimental methods for testing the performance of super-capacitors include the measurement of capacitance through charge and discharge, measurement of equivalent series resistance (ESR) and measurement of self-discharge and the equivalent circuit model (ECM) by electrochemical impedance spectroscopy (EIS). However, the methods are not suitable for the mass production line of supercapacitors since they require a long time for the test and several kinds of different instrument. EIS is an attractive method to evaluate the performance of supercapacitors except that it takes a long time for a single test. In this paper a fast EIS instrument suitable for quality assurance for the mass production of supercapacitors is proposed. In order to reduce the time for the test, a multi-sine sweeping method is used for the EIS test and the results are analyzed by extracting the parameters of the ECM to evaluate the performance of the supercapacitors. The proposed instrument is developed to have multi-channel to further decrease the time for the test with a supercapacitor. It is also presented as to how the extracted parameter values of the ECM can be used to evaluate the performance of the supercapacitor.

Synthesis of poly(methylcarbazole) and its nanoclay and nanozinc composites and corrosion protection performances on stainless steel Type 304

2017 ◽  
Vol 24 (6) ◽  
pp. 825-832 ◽  
Author(s):  
Murat Ates
Keyword(s):  
Stainless Steel ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Equivalent Circuit Model ◽  
Optical Microscope ◽  
Polarization Curves ◽  
Protective Behavior ◽  
Zn Nanoparticles

AbstractMethylcarbazole (MCz) and its nanocomposites with Montmorillonite nanoclay and Zn nanoparticles were chemically synthesized on a stainless steel (SS304) electrode. The modified electrode was characterized by optical microscope, scanning electron microscopy-energy dispersive X-ray analysis (SEM-EDX), Fourier-transform infrared spectroscopy-attenuated transmission reflectance (FTIR-ATR), four-point probe, and electrochemical impedance spectroscopy (EIS) analysis. The synthesized stainless steel/poly(methylcarbazole) (SS/P(MCz)), stainless steel/poly(methylcarbazole)/nanoclay (SS/P(MCz)/nanoclay), and stainless steel/poly(methylcarbazole)/nanoZn (SS/P(MCz)/nanoZn) were studied by potentiodynamic polarization curves. The protective behavior of these coatings in 3.5% NaCl as the corrosion medium was investigated using Tafel polarization curves, as well as electrochemical impedance spectroscopy. The corrosion protection parameters were also supported by EIS and an equivalent circuit model of Rs(Qc(Rc(QpRct))). The corrosion current of the SS/P(MCz)/nanoclay samples was found to be much lower (icorr=0.010 μA×cm-2) than that of SS/P(MCz)/nanoZn (icorr=0.031 μA×cm-2) and pure SS/P(MCz) samples. These results reveal that chemically synthesized SS/P(MCz), SS/P(MCz)/nanoclay, and SS/P(MCz)/nanoZn nanocomposite film coating have high corrosion protection efficiency (PE=99.56%, 99.89%, and 99.67%, respectively). Thus, based on the study findings, we posit that nanoclay and Zn nanoparticles possess favorable barrier properties, which can be employed in order to achieve improvements in chemical corrosion protection through P(MCz) coating.

Measuring and Modeling Analysis of Electrochemical Impedance Spectroscopy for Hydration Procedure of Cement Materials

2012 ◽  
Vol 588-589 ◽  
pp. 1033-1036 ◽  
Author(s):  
Xiang Ping Xian ◽  
Yan Shuai Wang ◽  
Feng Xing ◽  
Bi Qin Dong
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Equivalent Circuit ◽  
Electrochemical Impedance ◽  
Equivalent Circuit Model ◽  
Circuit Model ◽  
Cement Material ◽  
Capacitance Effect ◽  
Phase Transmission ◽  
Multi Phase

In this paper, the electrochemical impedance spectroscopy method is applied to characteristic the hydration procedure in cement materials. And a new equivalent circuit model is developed to express the hydration procedure of cement material. As cement paste is a complicated electrochemical system with multi-phase transmission, the equivalent circuit model is considered with the additional double layer capacitance effect at the interface among the hydration products in cement materials. It can express the electrochemical station in cement material, as the multi-phase mass transmission in the cement-based material during the hydration procedure.

scholarly journals Fuel Cell Fractional-Order Model via Electrochemical Impedance Spectroscopy

2021 ◽  
Vol 5 (1) ◽  
pp. 21
Author(s):  
Riccardo Caponetto ◽  
Fabio Matera ◽  
Emanuele Murgano ◽  
Emanuela Privitera ◽  
Maria Gabriella Xibilia
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Fuel Cell ◽  
Impedance Spectroscopy ◽  
Fractional Order ◽  
Proton Exchange Membrane ◽  
Electrochemical Impedance ◽  
Equivalent Circuit Model ◽  
Proton Exchange ◽  
Model Parameters ◽  
Data Driven Approach

The knowledge of the electrochemical processes inside a Fuel Cell (FC) is useful for improving FC diagnostics, and Electrochemical Impedance Spectroscopy (EIS) is one of the most used techniques for electrochemical characterization. This paper aims to propose the identification of a Fractional-Order Transfer Function (FOTF) able to represent the FC behavior in a set of working points. The model was identified by using a data-driven approach. Experimental data were obtained testing a Proton Exchange Membrane Fuel Cell (PEMFC) to measure the cell impedance. A genetic algorithm was firstly used to determine the sets of fractional-order impedance model parameters that best fit the input data in each analyzed working point. Then, a method was proposed to select a single set of parameters, which can represent the system behavior in all the considered working conditions. The comparison with an equivalent circuit model taken from the literature is reported, showing the advantages of the proposed approach.

scholarly journals Variable-Order Equivalent Circuit Modeling and State of Charge Estimation of Lithium-Ion Battery Based on Electrochemical Impedance Spectroscopy

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 769
Author(s):  
Ji’ang Zhang ◽  
Ping Wang ◽  
Yushu Liu ◽  
Ze Cheng
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Equivalent Circuit ◽  
Electrochemical Impedance ◽  
Equivalent Circuit Model ◽  
Lithium Ion ◽  
Impedance Spectrum ◽  
The State ◽  
State Of Charge ◽  
Variable Order

In the battery management system, it is important to accurately and efficiently estimate the state of charge (SOC) of lithium-ion batteries, which generally requires the establishment of a equivalent circuit model of the battery, whose accuracy and rationality play an important role in accurately estimating the state of lithium-ion batteries. The traditional single order equivalent circuit models do not take into account the changes of impedance spectrum under the action of multiple factors, nor do they take into account the balance of practicality and complexity of the model, resulting the low accuracy and poor practicability. In this paper, the theory of electrochemical impedance spectroscopy is used to guide and improve the equivalent circuit model. Based on the analysis of the variation of the high and intermediate frequency range of the impedance spectrum with the state of charge and temperature of the battery, a variable order equivalent model (VOEM) is proposed by Arrhenius equation and Bayesian information criterion (BIC), and the state equation and observation equation of VOEM are improved by autoregressive (AR) equations. Combined with the unscented Kalman filter (UKF), a SOC online estimation method is proposed, named VOEM-AR-UKF. The experimental results show that the proposed method has high accuracy and good adaptability.

scholarly journals Impact of normalization, standardization and pre-fit on the success rate of fitting in electrochemical impedance spectroscopy

2021 ◽  
Vol 7 (2) ◽  
pp. 492-495
Author(s):  
Norman Pfeiffer ◽  
Markus Jechow ◽  
Toni Wachter ◽  
Christian Hofmann ◽  
Abdelhamid Errachid ◽  
...  
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Success Rate ◽  
Electrochemical Impedance ◽  
Nonlinear Least Squares ◽  
User Input ◽  
Additional Signal ◽  
Initial Values ◽  
Fitting In ◽  
Parameter Values

Abstract Fitting the data of an electrochemical impedance spectroscopy (EIS) typically requires manual estimation of the initial values before regression algorithms such as complex nonlinear least squares (CNLS) can be applied. This makes the success rate of the fitting dependent on the user input. Furthermore, the Randles circuit consists of parameters with substantially differing magnitudes (e.g. capacitors and resistors), which can also strongly affect the success rate of the fitting due to numerical effects. The aim of this work is to investigate methods addressing the described limitations of fitting. Therefore, a Python implementation performing a fit for EIS is benchmarked with an equivalent open source library. The examined implementation optionally includes the normalization of the parameter values, the standardization of the impedances and a pre-fit. Applying the same equivalent circuit without additional signal processing steps and with fixed initial values defined by midpoints of the value ranges, both implementations were able to fit 46.50% of the simulated database with different spectra. Applying the normalization of the parameter values (76.25%) or the same method with additional pre-fit (97.75%) lead to a significant improvement of the success rate. The standardization of impedances did not affect the success rate.

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