Separation of predominant processes in electrochemical impedance spectra of lithium-ion batteries with nickel-manganese-cobalt cathodes

Sabet, Pouyan Shafiei; Sauer, Dirk Uwe

doi:10.1016/j.jpowsour.2019.03.068

Cited by 131 publications

(51 citation statements)

References 42 publications

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“…[1,2] The possibility to also investigate complex and unknown electrochemical systems via impedance spectroscopy turned the DRT method into a popular technique in recent impedance research. [3][4][5][6][7][8][9][10][11][12][13][14][15] However, calculat-ing DRT spectra from noisy experimental impedance data requires mathematical methods which are usually no black-box procedures. In particular, this indicates that certain preassumptions have to be made which strongly affect the calculations result.…”

Section: Introductionmentioning

confidence: 99%

Direct Access to the Optimal Regularization Parameter in Distribution of Relaxation Times Analysis

2020

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The distribution of times (DRT) method has become an important extension for electrochemical impedance investigations. Calculating the DRT is particularly advantageous for complex systems, as it yields an increased resolution in frequency domain. However, the determination of the DRT from experimental impedance data requires special mathematical effort. An often‐used method for the calculation of the DRT is the Tikhonov regularization. The quality of the result of this method depends on the choice of a suitable regularization parameter. This parameter has to be selected by the user. In a former work (N. Schlüter, S. Ernst, U. Schröder, ChemElectroChem 2019, 6, 6027–6037), we showed a method that helps to find the best regularization parameter for given impedance data. However, this test was based on repetitive impedance measurements, which have to be performed at least twice. In this paper, we optimize our previous method to assure the determination of an optimal regularization parameter from just one single impedance spectrum. Eventually, this revision saves measurement time and makes our test also applicable for less time stable measurements.

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Section: Introductionmentioning

confidence: 99%

Direct Access to the Optimal Regularization Parameter in Distribution of Relaxation Times Analysis

2020

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“…The Distribution of Relaxation Times (DRT) method is suitable to overcome these issues. [10][11][12][13] By deconvoluting the collected impedance spectra from frequency domain to time domain it significantly increases the resolution of the respective impedance data. As a result, the isolated time constants of the system's electrochemical processes become directly observable.…”

Section: Introductionmentioning

confidence: 99%

Quality‐Indicator‐Based Preprocessing for the Distribution of Relaxation Times Method

et al. 2021

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The deconvolution of impedance data to their respective distribution of relaxation times (DRT) is accompanied by an increase in the resolution of the frequency domain and is, thus, advantageous. Yet, most of the techniques used for computing DRT spectra from experimental data are valid only for impedance spectra that solely show polarization processes. Therefore, most experimental electrochemical impedance spectra must be corrected from perturbing inductive, capacitive, or diffusive contributions. This preprocessing is time consuming, and its quality has an enormous impact on the obtained DRT spectra. It also prohibits using the DRT method within an automated impedance evaluation. In this work, we propose a software-aided approach for deriving optimal preprocessing. For this purpose, we first introduce a quality indicator that reflects the quality of a certain preprocessing. Based on this quality indicator, we furthermore introduce a new batch fitting approach for deriving the optimal equivalent electrical circuit within the preprocessing of experimental impedance spectra. Besides, the batch fitting displays the optimal frequency range for modeling the unwanted impedance fractions. Based on this information, the considered impedance data can finally be optimally corrected from any non-polarization processes. The new methods and their application are tested for simulated data and experimental impedance data of a lithium-ion cell.

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“…Electrochemical impedance spectroscopy (EIS) has been proven to be a powerful tool for the diagnosis of complex electrochemical systems, including lithium-ion batteries [1][2][3][4][5][6], fuel cells [7,8], and supercapacitors [9,10]. Electrochemical impedance spectroscopy has been widely used to characterize the polarization processes of lithium-ion batteries [11][12][13][14] and to investigate various prognostics and health management (PHM) methods [15][16][17][18][19]. Electrochemical impedance spectrum is generally analyzed by a carefully chosen equivalent-circuit model (ECM), which requires knowledge about the electrochemical processes that take place at the individual electrodes within the cell [20][21][22][23].…”

Section: Introductionmentioning

confidence: 99%

Determination of the Differential Capacity of Lithium-Ion Batteries by the Deconvolution of Electrochemical Impedance Spectra

Guo

Yang

Guo³

et al. 2020

Energies

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Electrochemical impedance spectroscopy (EIS) is a powerful tool for investigating electrochemical systems, such as lithium-ion batteries or fuel cells, given its high frequency resolution. The distribution of relaxation times (DRT) method offers a model-free approach for a deeper understanding of EIS data. However, in lithium-ion batteries, the differential capacity caused by diffusion processes is non-negligible and cannot be decomposed by the DRT method, which limits the applicability of the DRT method to lithium-ion batteries. In this study, a joint estimation method with Tikhonov regularization is proposed to estimate the differential capacity and the DRT simultaneously. Moreover, the equivalence of the differential capacity and the incremental capacity is proven. Different types of commercial lithium-ion batteries are tested to validate the joint estimation method and to verify the equivalence. The differential capacity is shown to be a promising approach to the evaluation of the state-of-health (SOH) of lithium-ion batteries based on its equivalence with the incremental capacity.

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Separation of predominant processes in electrochemical impedance spectra of lithium-ion batteries with nickel-manganese-cobalt cathodes

Cited by 131 publications

References 42 publications

Direct Access to the Optimal Regularization Parameter in Distribution of Relaxation Times Analysis

Direct Access to the Optimal Regularization Parameter in Distribution of Relaxation Times Analysis

Quality‐Indicator‐Based Preprocessing for the Distribution of Relaxation Times Method

Determination of the Differential Capacity of Lithium-Ion Batteries by the Deconvolution of Electrochemical Impedance Spectra

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