Towards a practical tool for online monitoring of solid oxide fuel cell operation: An experimental study and application of advanced data analysis approaches

Subotić, Vanja; Stoeckl, Bernhard; Lawlor, V.; Strasser, Johannes; Schroettner, Hartmuth; Hochenauer, Christoph

doi:10.1016/j.apenergy.2018.03.182

Cited by 59 publications

(40 citation statements)

References 38 publications

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“…This might correlate to the non-linear part of the current-voltage curve of ID1 presented in Fig. 6a and therefore to higher activation losses as described in [22].…”

Section: H 2 Omentioning

confidence: 79%

“…A decreasing activation polarization results in a linearization of the current-voltage correlation (polarization curve), which is clearly visible in the operating range of low current densities. The impact of fuel starvation, which causes concentration losses, is visible at high current densities, as theoretically described in [21] and experimentally approved in [22]. Hence, a linear current-voltage correlation results in a more stable operation behavior due to better controllability of the cell.…”

Section: Sofc Operation With Gas Components From a Product Gas: A Reviewmentioning

confidence: 91%

“…5. This increases the linearity of the current-voltage correlation of a cell at low electric loads as described in [22] for H 2 oxidation in presence of H 2 O and in [25] for CO oxidation in presence of CO 2 . The investigated cell showed a non-linear voltage response when fueled with gas composition ID1 (5 vol% H 2 O) in the low load range, which can be seen in Fig.…”

Section: H 2 Omentioning

confidence: 95%

“…Studies on dry H 2 /N 2 mixtures are neglected in this paper due to minor relevance for biomass gasifiers. Moreover, it is generally known that an increase of the nitrogen compound leads to a performance decrease due to (i) a lower partial pressure of the fuel gases and therefore a lower chemical potential (dilution effect) and (ii) higher diffusion losses of the reactive species to the active centers (concentration polarization) as presented in [22,28].…”

Section: Parameter Studymentioning

confidence: 99%

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Investigation of solid oxide fuel cell operation with synthetic biomass gasification product gases as a basis for enhancing its performance

Pongratz

Subotić

Schroettner

et al. 2020

Biomass Conv. Bioref.

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Solid oxide fuel cells represent a promising technology to increase the electrical efficiency of biomass-based combined-heat-power systems in comparison to state-of-the-art gas engines, additionally providing high temperature heat. To identify favorable fuel gas compositions for an efficient coupling with gasifiers at low degradation risk is of major importance to ensure stability, reliability, and durability of the systems used, thus increasing attractiveness of electricity production from biomass. Therefore, this study presents a comprehensive analysis on the influence of main gas components from biomass gasification on the performance and efficiency of a cell relevant for real application. An industrial-size electrolyte supported single cell with nickel/gadolinium-doped ceria anode was selected showing high potential for gasifier-solid oxide fuel cell systems. Beneficial gas component ratios enhancing the power output and electric efficiency are proposed based on the experimental study performed. Furthermore, the degradation stability of a SOFC fueled with a synthetic product gas representing steam gasification of woody biomass was investigated. After 500 h of operation under load at a steam-to-carbon ratio of 2.25 in the fuel gas, no performance or anode degradation could be detected.

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“…This might correlate to the non-linear part of the current-voltage curve of ID1 presented in Fig. 6a and therefore to higher activation losses as described in [22].…”

Section: H 2 Omentioning

confidence: 79%

Section: Sofc Operation With Gas Components From a Product Gas: A Reviewmentioning

confidence: 91%

Section: H 2 Omentioning

confidence: 95%

Section: Parameter Studymentioning

confidence: 99%

See 2 more Smart Citations

Investigation of solid oxide fuel cell operation with synthetic biomass gasification product gases as a basis for enhancing its performance

Pongratz

Subotić

Schroettner

et al. 2020

Biomass Conv. Bioref.

View full text Add to dashboard Cite

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“…This method is further associated with an improved data resolution in frequency domain . Thus, due to its potential towards advanced data analysis, its application has gained popularity in recent impedance research . Nevertheless, the calculation of DRT plots is an intrinsically ill‐posed problem and regularization methods are needed .…”

Section: Introductionmentioning

confidence: 99%

Finding the Optimal Regularization Parameter in Distribution of Relaxation Times Analysis

2019

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The distribution of relaxation times (DRT) method allows the direct interpretation of electrochemical impedance data, yielding an increased resolution in the frequency domain. Calculating the DRT from experimental impedance spectra, however, is an intrinsically ill‐posed problem requiring special mathematical treatments such as, for example, the Tikhonov regularization. In this study, we propose a new approach for finding optimal regularization parameters in the Tikhonov regularization. The new test function is based on repetitive impedance measurements and a simple data resampling with a subsequent variance investigation. Furthermore, our new approach is combined with already published procedures considering the determination of best regularization parameters. Here, the combination of several tests enables a clear assignment of an upper and a lower boundary for suitable regularization parameters. Finally, both tests were applied to simulated as well as to experimental impedance data for validation. To analyze the sensitivity of the approach, varying error extent was generated to the synthetic and experimental measurements.

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Nonlinear Electrochemical Analysis: Worth the Effort to Reveal New Insights into Energy Materials

Schlüter

Novák

Schröder

2022

Advanced Energy Materials

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and the effectiveness and durability of the materials applied, researchers always call for reliable and detailed knowledge of the mechanism(s) of both, main and side reactions, and especially for their kinetics. In order to gain the relevant information, a large number of methods have been proposed to characterize battery materials, battery electrodes and their interfaces, and battery cells. But when samples are taken out of the cells and analyzed later, there is a high risk of both, contamination and changes due to possible relaxation processes, and the challenge is to draw sound conclusions in respect to a "living and breathing" battery cell, i.e., to a cell under current flow (cf. Figure 1). Therefore, the so-called in situ and operando (and often online) methods are preferred. Sometimes they are the only option to collect relevant data to understand and improve materials for energy systems. [5] In many cases, results from different techniques need to be combined to obtain sound conclusions. [6,7] The terminology for the aforementioned methods shifted during the last decade and is not always consistent throughout the literature. Nowadays, the general understanding is as follows: An operando experiment means a characterization experiment in an electrochemical cell (e.g., battery, fuel cell, electrolyzer) under current flow, with either the potential or the current controlled. One of the many examples is the operando neutron powder diffraction, a technique analyzing the changes in the structure of battery materials in "real" battery cells under current flow with the help of neutron diffraction. [9] Another example is the operando X-ray photoelectron spectroscopy experiment (normally limited to vacuum-compatible cells with nonvolatile electrolytes) providing information about the changes of the chemical composition of the interfacial species with the potential. [10,11] An in situ experiment is also an experiment in a battery cell, however, the current flow is interrupted when the data are collected. An example here is the in situ X-ray absorption spectroscopy (XAS) experiment in which the cell has to be disconnected for technical reasons during the operation of the detector [7] or the tomography of energy materials by means of neutron or X-ray source. [12,13] Online techniques are understood here as either continuously or periodically analyzed samples that are taken out of the electrochemical cell. A typical example is the online (differential) electrochemical mass spectrometry (often shortened as online electrochemical mass spectrometry (OEMS)/differential electrochemical mass spectrometry (DEMS)) analyzing the volatile products of electrochemical reactions with the help of a mass spectrometer by

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Towards a practical tool for online monitoring of solid oxide fuel cell operation: An experimental study and application of advanced data analysis approaches

Cited by 59 publications

References 38 publications

Investigation of solid oxide fuel cell operation with synthetic biomass gasification product gases as a basis for enhancing its performance

Investigation of solid oxide fuel cell operation with synthetic biomass gasification product gases as a basis for enhancing its performance

Finding the Optimal Regularization Parameter in Distribution of Relaxation Times Analysis

Nonlinear Electrochemical Analysis: Worth the Effort to Reveal New Insights into Energy Materials

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