The Experts below are selected from a list of 105 Experts worldwide ranked by ideXlab platform
Olivier Lottin - One of the best experts on this subject based on the ideXlab platform.
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Impact of Gas Stoichiometry on the Result of Accelerated Stress Tests
2018Co-Authors: Julia Mainka, Jérôme Dillet, Said Ait Hammou Taleb, Olivier LottinAbstract:Text: Degradation issues remain among the main factors impeding the development of commercially viable fuel cell (FC) systems for transportation and stationary power applications. The necessity to keep costs and performances at reasonable levels led to the widespread use of carbon supported platinum (Pt) for electrodes and thin PFSA membranes as electrolyte. Both are quite fragile materials but currently without any convincing alternative. To better understand, and eventually limit degradation mechanisms, several kinds of accelerated stress tests (AST) have been developed targeting each material independently: namely open circuit voltage (OCV) for PFSA membranes, potentiostatic regimes for carbon, and potential cycling for Pt [1, 2]. Other accelerated stress tests corresponding to common fuel cell operation sequences were also proposed like constant current, start/stop, hydrogen starvation/dead-ended anode protocols [3,4], temperature, relative humidity or potential/load cycling, or even freeze/thaw protocols [5]. In this work, we focus on load cycling events, which are very close to the potential cycling performed during AST to study Pt and carbon degradation mechanisms. For obvious reasons, load cycling in actual fuel cell systems and potential cycling in AST are usually performed in overfed conditions [6]: i.e. the fuel cell is supplied with the gas flow rates corresponding to the highest current before the intensity increases. And in most of the cases, the gas flow rates are even permanently kept at the highest values during AST. To avoid supplying fuel and air in excess, most of fuel cell stacks are hybridized either with batteries or supercapacitors (SC) to improve the system dynamics (which in return increases its size and cost). Thanks to hybridization, the FC voltage can drop by a few hundreds of mV per cell during the time needed by the gas supply lines to adapt the flow rates, while batteries or SC keep the system power at the required value. However, the impact of such short reactant starvation events on FC performance and durability is not very well known. Therefore, we performed repeated current Heaviside steps as AST on PEM single cells; typical values were from 0.25 to 0.95 A/cm² (with corresponding FC voltages between 0.65 and 0.8 V). The gas flow rates were set either to the maximum current intensity (with air and H 2 stoichiometries of 3 and 1.5 in open-anode or 1 in dead-end mode, respectively) or we let the gas lines adjust the flow rates when the current input changed, which took about half a second (during this time, the FC could fell to about 0.1 V). As shown on the Figure, the performance and electrochemical surface area repeatedly aged significantly slower in the second case, i.e. with short gas starvation events. To better understand this difference, similar experiments were performed in a segmented cell [7] with measurements of Local currents, anode and Cathode potentials. We observed that Local Cathode potentials were higher in overfed conditions while they dropped for a short time in the other case due to (most probably) oxygen depletion in the Cathode compartment. Local negative currents were also observed sometimes when the load decreased, but since they were not associated to high Local potentials, they did not worsen degradation. In the same way, since the FC dynamics were limited most probably by air supply, the anode (and thus Cathode) Local potentials remained low. These results suggest that FC voltage drops during transients due to short lacks of reactants can improve the durability of the catalyst layer, as well as optimize the system efficiency in terms of hydrogen ubmission Completed
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High Potential Excursions during PEM Fuel Cell Operation with Dead-Ended Anode
Journal of The Electrochemical Society, 2015Co-Authors: Sofyane Abbou, Jérôme Dillet, Dusan Spernjak, Rangachary Mukundan, Rod L. Borup, Gaël Maranzana, Olivier LottinAbstract:International audienceOperating a proton exchange membrane (PEM) fuel cell with a dead-ended anode may lead to Local fuel starvation due to the excessive accumulation of liquid water and possibly nitrogen (because of membrane crossover) in the anode compartment. In this paper, we present experimental results obtained with a segmented, linear cell with reference electrodes along the gas channels, used to record Local anode and Cathode potentials. By simultaneously monitoring the Local potentials and current densities during operation, we assessed the impact of fuel starvation on Local fuel cell performance during aging protocols consisting of repeated dead-ended anode operation sequences (with anode outlet closed longer than in real use conditions). During the aging protocols, we observed strong Local Cathode potential excursions close to the anode outlet. The Cathode showed non-uniform ElectroChemical Surface Area (ECSA) losses and performance degradation along the cell area. The damage was more severe in the regions suffering the longest from fuel starvation. Similar experiments performed in different operating conditions and with different membrane thickness showed that water management impacts significantly the Cathode potential variations and thus the MEA degradation. Most of the MEA degradation is attributed to Local Cathode potential excursions above 1.2 V although potential cycling between 0.5 V and 0.7 V also had an impact in the regions well supplied with hydrogen (hydrogen purges were triggered when the fuel cell voltage dropped from about 0.7 V to 0.5 V). According to our results, Localized and transient hydrogen starvation events may be difficult to detect by considering only the overall fuel cell performance
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High Potential Excursions during PEM Fuel Cell Operation with Dead-Ended Anode
Journal of The Electrochemical Society, 2015Co-Authors: Sofyane Abbou, Jérôme Dillet, Dusan Spernjak, Rangachary Mukundan, Rod L. Borup, Gaël Maranzana, Olivier LottinAbstract:Operating a proton exchange membrane (PEM) fuel cell with a dead-ended anode may lead to Local fuel starvation due to the excessive accumulation of liquid water and possibly nitrogen (because of membrane crossover) in the anode compartment. In this paper, we present experimental results obtained with a segmented, linear cell with reference electrodes along the gas channels, used to record Local anode and Cathode potentials. By simultaneously monitoring the Local potentials and current densities during operation, we assessed the impact of fuel starvation on Local fuel cell performance during aging protocols consisting of repeated dead-ended anode operation sequences (with anode outlet closed longer than in real use conditions). During the aging protocols, we observed strong Local Cathode potential excursions close to the anode outlet. The Cathode showed non-uniform ElectroChemical Surface Area (ECSA) losses and performance degradation along the cell area. The damage was more severe in the regions suffering the longest from fuel starvation. Similar experiments performed in different operating conditions and with different membrane thickness showed that water management impacts significantly the Cathode potential variations and thus the MEA degradation. Most of the MEA degradation is attributed to Local Cathode potential excursions above 1.2 V although potential cycling between 0.5 V and 0.7 V also had an impact in the regions well supplied with hydrogen (hydrogen purges were triggered when the fuel cell voltage dropped from about 0.7 V to 0.5 V). According to our results, Localized and transient hydrogen starvation events may be difficult to detect by considering only the overall fuel cell performance.
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Time Evolution of Local Potentials During PEM Fuel Cell Operation With Dead-Ended Anode
ECS Transactions, 2013Co-Authors: Sofyane Abbou, Jérôme Dillet, Dusan Spernjak, Rangachary Mukundan, Joseph D. Fairweather, Rod L. Borup, Gaël Maranzana, Sophie Didierjean, Olivier LottinAbstract:We present experimental results obtained with a 2D segmented cell with reference electrodes along the gas channels, used to record Local anode and Cathode potentials. Aging protocols consisting of repeated dead-end operation sequences were performed to assess the impact of hydrogen starvation on the Local fuel cell performance. We observed strong Local Cathode potential excursion, as well as non-uniform ECSA losses and performance degradation along the cell area. The damage was more pronounced in the regions suffering the longest from fuel starvation: i.e. close to the exit of the anode compartment.
Martin Stratmann - One of the best experts on this subject based on the ideXlab platform.
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The delamination of polymeric coatings from electrogalvanised steel – A mechanistic approach. Part 1: delamination from a defect with intact zinc layer
Corrosion Science, 2001Co-Authors: W. Fürbeth, Martin StratmannAbstract:Abstract The basic mechanism of the cathodic delamination of polymer films from zinc-coated steel starting from a defect with an intact zinc layer has been derived. Scanning Kelvinprobe and ESCA measurements have been carried out with a very simple model system. The delamination is presented as the formation of a galvanic element between the active defect and the delamination front with electrons and cations being transported to the Local Cathode. The oxygen reduction in the delaminated area leads to an alkalinisation of the zinc/polymer interface resulting in a significant growth of the oxide layer.
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The Delamination of Polymeric Coatings from Steel. Part 1: Calibration of the Kelvinprobe and basic delamination mechanism
Corrosion Science, 1998Co-Authors: A. Leng, H. Streckel, Martin StratmannAbstract:Abstract In the first part of this study are presented the theory and the experimental techniques which are necessary to investigate the delamination of model coatings on steel. It is shown that the electrochemical reactions taking place at the substrate/electrolyte and substrate/polymer interfaces are responsible for delamination. Due to the fact that the electrochemical reactions are accompanied by changes in the corrosion potential, it is possible to identify and follow the delamination by measuring the corrosion potential as a function of time and Local position. Furthermore, it is demonstrated that the Volta-potential difference between a reference metal and the model polymer surface is determined by the corrosion potential, whereas the influence of the Donnan-potential is small and constant. By combining several experimental techniques, like the Scanning Kelvinprobe, Auger electron spectroscopy and mechanical de-adhesion tests, the delamination process is studied in detail and a model is presented, which is based on the existence of a galvanic element at the substrate/polymer interface. The uncoated iron is the Local anode, where the iron dissolution predominates, whereas the delaminated part represents the Local Cathode and, within this area, only the oxygen reduction takes place. The second and third part of this paper deal with an experimental verification of this model.
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Investigation of the delamination of polymer films from galvanized steel with the Scanning Kelvinprobe
Fresenius' Journal of Analytical Chemistry, 1995Co-Authors: W. Fürbeth, Martin StratmannAbstract:The applicability of a new experimental technique – the Scanning Kelvinprobe – for the analysis of the delamination of polymer films from galvanized steel is discussed. Defect ions having direct access to the zinc/ polymer interface will diffuse along this interface, a process, which can be monitored by the Kelvinprobe in a very early state with a high Local resolution. After incorporation of ions a galvanic element is formed, the Local Cathode being at the delamination front, where oxygen is reduced, and the Local anode at the zinc coated defect. For the model polymer under investigation the interaction between the film and the substrate is weak and the rate determining step for the delamination is the diffusion of cations from the Local anode to the Local Cathode. An exposure to a highly CO_2-containing atmosphere before the delamination prolongs the incubation time of delamination. If there is no zinc layer at the defect, an anodic delamination mechanism occurs. Zinc is dissolved under the polymer film, while the steel surface is cathodically protected.
Sofyane Abbou - One of the best experts on this subject based on the ideXlab platform.
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High Potential Excursions during PEM Fuel Cell Operation with Dead-Ended Anode
Journal of The Electrochemical Society, 2015Co-Authors: Sofyane Abbou, Jérôme Dillet, Dusan Spernjak, Rangachary Mukundan, Rod L. Borup, Gaël Maranzana, Olivier LottinAbstract:International audienceOperating a proton exchange membrane (PEM) fuel cell with a dead-ended anode may lead to Local fuel starvation due to the excessive accumulation of liquid water and possibly nitrogen (because of membrane crossover) in the anode compartment. In this paper, we present experimental results obtained with a segmented, linear cell with reference electrodes along the gas channels, used to record Local anode and Cathode potentials. By simultaneously monitoring the Local potentials and current densities during operation, we assessed the impact of fuel starvation on Local fuel cell performance during aging protocols consisting of repeated dead-ended anode operation sequences (with anode outlet closed longer than in real use conditions). During the aging protocols, we observed strong Local Cathode potential excursions close to the anode outlet. The Cathode showed non-uniform ElectroChemical Surface Area (ECSA) losses and performance degradation along the cell area. The damage was more severe in the regions suffering the longest from fuel starvation. Similar experiments performed in different operating conditions and with different membrane thickness showed that water management impacts significantly the Cathode potential variations and thus the MEA degradation. Most of the MEA degradation is attributed to Local Cathode potential excursions above 1.2 V although potential cycling between 0.5 V and 0.7 V also had an impact in the regions well supplied with hydrogen (hydrogen purges were triggered when the fuel cell voltage dropped from about 0.7 V to 0.5 V). According to our results, Localized and transient hydrogen starvation events may be difficult to detect by considering only the overall fuel cell performance
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High Potential Excursions during PEM Fuel Cell Operation with Dead-Ended Anode
Journal of The Electrochemical Society, 2015Co-Authors: Sofyane Abbou, Jérôme Dillet, Dusan Spernjak, Rangachary Mukundan, Rod L. Borup, Gaël Maranzana, Olivier LottinAbstract:Operating a proton exchange membrane (PEM) fuel cell with a dead-ended anode may lead to Local fuel starvation due to the excessive accumulation of liquid water and possibly nitrogen (because of membrane crossover) in the anode compartment. In this paper, we present experimental results obtained with a segmented, linear cell with reference electrodes along the gas channels, used to record Local anode and Cathode potentials. By simultaneously monitoring the Local potentials and current densities during operation, we assessed the impact of fuel starvation on Local fuel cell performance during aging protocols consisting of repeated dead-ended anode operation sequences (with anode outlet closed longer than in real use conditions). During the aging protocols, we observed strong Local Cathode potential excursions close to the anode outlet. The Cathode showed non-uniform ElectroChemical Surface Area (ECSA) losses and performance degradation along the cell area. The damage was more severe in the regions suffering the longest from fuel starvation. Similar experiments performed in different operating conditions and with different membrane thickness showed that water management impacts significantly the Cathode potential variations and thus the MEA degradation. Most of the MEA degradation is attributed to Local Cathode potential excursions above 1.2 V although potential cycling between 0.5 V and 0.7 V also had an impact in the regions well supplied with hydrogen (hydrogen purges were triggered when the fuel cell voltage dropped from about 0.7 V to 0.5 V). According to our results, Localized and transient hydrogen starvation events may be difficult to detect by considering only the overall fuel cell performance.
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Time Evolution of Local Potentials During PEM Fuel Cell Operation With Dead-Ended Anode
ECS Transactions, 2013Co-Authors: Sofyane Abbou, Jérôme Dillet, Dusan Spernjak, Rangachary Mukundan, Joseph D. Fairweather, Rod L. Borup, Gaël Maranzana, Sophie Didierjean, Olivier LottinAbstract:We present experimental results obtained with a 2D segmented cell with reference electrodes along the gas channels, used to record Local anode and Cathode potentials. Aging protocols consisting of repeated dead-end operation sequences were performed to assess the impact of hydrogen starvation on the Local fuel cell performance. We observed strong Local Cathode potential excursion, as well as non-uniform ECSA losses and performance degradation along the cell area. The damage was more pronounced in the regions suffering the longest from fuel starvation: i.e. close to the exit of the anode compartment.
Jérôme Dillet - One of the best experts on this subject based on the ideXlab platform.
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Impact of Gas Stoichiometry on the Result of Accelerated Stress Tests
2018Co-Authors: Julia Mainka, Jérôme Dillet, Said Ait Hammou Taleb, Olivier LottinAbstract:Text: Degradation issues remain among the main factors impeding the development of commercially viable fuel cell (FC) systems for transportation and stationary power applications. The necessity to keep costs and performances at reasonable levels led to the widespread use of carbon supported platinum (Pt) for electrodes and thin PFSA membranes as electrolyte. Both are quite fragile materials but currently without any convincing alternative. To better understand, and eventually limit degradation mechanisms, several kinds of accelerated stress tests (AST) have been developed targeting each material independently: namely open circuit voltage (OCV) for PFSA membranes, potentiostatic regimes for carbon, and potential cycling for Pt [1, 2]. Other accelerated stress tests corresponding to common fuel cell operation sequences were also proposed like constant current, start/stop, hydrogen starvation/dead-ended anode protocols [3,4], temperature, relative humidity or potential/load cycling, or even freeze/thaw protocols [5]. In this work, we focus on load cycling events, which are very close to the potential cycling performed during AST to study Pt and carbon degradation mechanisms. For obvious reasons, load cycling in actual fuel cell systems and potential cycling in AST are usually performed in overfed conditions [6]: i.e. the fuel cell is supplied with the gas flow rates corresponding to the highest current before the intensity increases. And in most of the cases, the gas flow rates are even permanently kept at the highest values during AST. To avoid supplying fuel and air in excess, most of fuel cell stacks are hybridized either with batteries or supercapacitors (SC) to improve the system dynamics (which in return increases its size and cost). Thanks to hybridization, the FC voltage can drop by a few hundreds of mV per cell during the time needed by the gas supply lines to adapt the flow rates, while batteries or SC keep the system power at the required value. However, the impact of such short reactant starvation events on FC performance and durability is not very well known. Therefore, we performed repeated current Heaviside steps as AST on PEM single cells; typical values were from 0.25 to 0.95 A/cm² (with corresponding FC voltages between 0.65 and 0.8 V). The gas flow rates were set either to the maximum current intensity (with air and H 2 stoichiometries of 3 and 1.5 in open-anode or 1 in dead-end mode, respectively) or we let the gas lines adjust the flow rates when the current input changed, which took about half a second (during this time, the FC could fell to about 0.1 V). As shown on the Figure, the performance and electrochemical surface area repeatedly aged significantly slower in the second case, i.e. with short gas starvation events. To better understand this difference, similar experiments were performed in a segmented cell [7] with measurements of Local currents, anode and Cathode potentials. We observed that Local Cathode potentials were higher in overfed conditions while they dropped for a short time in the other case due to (most probably) oxygen depletion in the Cathode compartment. Local negative currents were also observed sometimes when the load decreased, but since they were not associated to high Local potentials, they did not worsen degradation. In the same way, since the FC dynamics were limited most probably by air supply, the anode (and thus Cathode) Local potentials remained low. These results suggest that FC voltage drops during transients due to short lacks of reactants can improve the durability of the catalyst layer, as well as optimize the system efficiency in terms of hydrogen ubmission Completed
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High Potential Excursions during PEM Fuel Cell Operation with Dead-Ended Anode
Journal of The Electrochemical Society, 2015Co-Authors: Sofyane Abbou, Jérôme Dillet, Dusan Spernjak, Rangachary Mukundan, Rod L. Borup, Gaël Maranzana, Olivier LottinAbstract:International audienceOperating a proton exchange membrane (PEM) fuel cell with a dead-ended anode may lead to Local fuel starvation due to the excessive accumulation of liquid water and possibly nitrogen (because of membrane crossover) in the anode compartment. In this paper, we present experimental results obtained with a segmented, linear cell with reference electrodes along the gas channels, used to record Local anode and Cathode potentials. By simultaneously monitoring the Local potentials and current densities during operation, we assessed the impact of fuel starvation on Local fuel cell performance during aging protocols consisting of repeated dead-ended anode operation sequences (with anode outlet closed longer than in real use conditions). During the aging protocols, we observed strong Local Cathode potential excursions close to the anode outlet. The Cathode showed non-uniform ElectroChemical Surface Area (ECSA) losses and performance degradation along the cell area. The damage was more severe in the regions suffering the longest from fuel starvation. Similar experiments performed in different operating conditions and with different membrane thickness showed that water management impacts significantly the Cathode potential variations and thus the MEA degradation. Most of the MEA degradation is attributed to Local Cathode potential excursions above 1.2 V although potential cycling between 0.5 V and 0.7 V also had an impact in the regions well supplied with hydrogen (hydrogen purges were triggered when the fuel cell voltage dropped from about 0.7 V to 0.5 V). According to our results, Localized and transient hydrogen starvation events may be difficult to detect by considering only the overall fuel cell performance
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High Potential Excursions during PEM Fuel Cell Operation with Dead-Ended Anode
Journal of The Electrochemical Society, 2015Co-Authors: Sofyane Abbou, Jérôme Dillet, Dusan Spernjak, Rangachary Mukundan, Rod L. Borup, Gaël Maranzana, Olivier LottinAbstract:Operating a proton exchange membrane (PEM) fuel cell with a dead-ended anode may lead to Local fuel starvation due to the excessive accumulation of liquid water and possibly nitrogen (because of membrane crossover) in the anode compartment. In this paper, we present experimental results obtained with a segmented, linear cell with reference electrodes along the gas channels, used to record Local anode and Cathode potentials. By simultaneously monitoring the Local potentials and current densities during operation, we assessed the impact of fuel starvation on Local fuel cell performance during aging protocols consisting of repeated dead-ended anode operation sequences (with anode outlet closed longer than in real use conditions). During the aging protocols, we observed strong Local Cathode potential excursions close to the anode outlet. The Cathode showed non-uniform ElectroChemical Surface Area (ECSA) losses and performance degradation along the cell area. The damage was more severe in the regions suffering the longest from fuel starvation. Similar experiments performed in different operating conditions and with different membrane thickness showed that water management impacts significantly the Cathode potential variations and thus the MEA degradation. Most of the MEA degradation is attributed to Local Cathode potential excursions above 1.2 V although potential cycling between 0.5 V and 0.7 V also had an impact in the regions well supplied with hydrogen (hydrogen purges were triggered when the fuel cell voltage dropped from about 0.7 V to 0.5 V). According to our results, Localized and transient hydrogen starvation events may be difficult to detect by considering only the overall fuel cell performance.
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Time Evolution of Local Potentials During PEM Fuel Cell Operation With Dead-Ended Anode
ECS Transactions, 2013Co-Authors: Sofyane Abbou, Jérôme Dillet, Dusan Spernjak, Rangachary Mukundan, Joseph D. Fairweather, Rod L. Borup, Gaël Maranzana, Sophie Didierjean, Olivier LottinAbstract:We present experimental results obtained with a 2D segmented cell with reference electrodes along the gas channels, used to record Local anode and Cathode potentials. Aging protocols consisting of repeated dead-end operation sequences were performed to assess the impact of hydrogen starvation on the Local fuel cell performance. We observed strong Local Cathode potential excursion, as well as non-uniform ECSA losses and performance degradation along the cell area. The damage was more pronounced in the regions suffering the longest from fuel starvation: i.e. close to the exit of the anode compartment.
Rangachary Mukundan - One of the best experts on this subject based on the ideXlab platform.
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High Potential Excursions during PEM Fuel Cell Operation with Dead-Ended Anode
Journal of The Electrochemical Society, 2015Co-Authors: Sofyane Abbou, Jérôme Dillet, Dusan Spernjak, Rangachary Mukundan, Rod L. Borup, Gaël Maranzana, Olivier LottinAbstract:International audienceOperating a proton exchange membrane (PEM) fuel cell with a dead-ended anode may lead to Local fuel starvation due to the excessive accumulation of liquid water and possibly nitrogen (because of membrane crossover) in the anode compartment. In this paper, we present experimental results obtained with a segmented, linear cell with reference electrodes along the gas channels, used to record Local anode and Cathode potentials. By simultaneously monitoring the Local potentials and current densities during operation, we assessed the impact of fuel starvation on Local fuel cell performance during aging protocols consisting of repeated dead-ended anode operation sequences (with anode outlet closed longer than in real use conditions). During the aging protocols, we observed strong Local Cathode potential excursions close to the anode outlet. The Cathode showed non-uniform ElectroChemical Surface Area (ECSA) losses and performance degradation along the cell area. The damage was more severe in the regions suffering the longest from fuel starvation. Similar experiments performed in different operating conditions and with different membrane thickness showed that water management impacts significantly the Cathode potential variations and thus the MEA degradation. Most of the MEA degradation is attributed to Local Cathode potential excursions above 1.2 V although potential cycling between 0.5 V and 0.7 V also had an impact in the regions well supplied with hydrogen (hydrogen purges were triggered when the fuel cell voltage dropped from about 0.7 V to 0.5 V). According to our results, Localized and transient hydrogen starvation events may be difficult to detect by considering only the overall fuel cell performance
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High Potential Excursions during PEM Fuel Cell Operation with Dead-Ended Anode
Journal of The Electrochemical Society, 2015Co-Authors: Sofyane Abbou, Jérôme Dillet, Dusan Spernjak, Rangachary Mukundan, Rod L. Borup, Gaël Maranzana, Olivier LottinAbstract:Operating a proton exchange membrane (PEM) fuel cell with a dead-ended anode may lead to Local fuel starvation due to the excessive accumulation of liquid water and possibly nitrogen (because of membrane crossover) in the anode compartment. In this paper, we present experimental results obtained with a segmented, linear cell with reference electrodes along the gas channels, used to record Local anode and Cathode potentials. By simultaneously monitoring the Local potentials and current densities during operation, we assessed the impact of fuel starvation on Local fuel cell performance during aging protocols consisting of repeated dead-ended anode operation sequences (with anode outlet closed longer than in real use conditions). During the aging protocols, we observed strong Local Cathode potential excursions close to the anode outlet. The Cathode showed non-uniform ElectroChemical Surface Area (ECSA) losses and performance degradation along the cell area. The damage was more severe in the regions suffering the longest from fuel starvation. Similar experiments performed in different operating conditions and with different membrane thickness showed that water management impacts significantly the Cathode potential variations and thus the MEA degradation. Most of the MEA degradation is attributed to Local Cathode potential excursions above 1.2 V although potential cycling between 0.5 V and 0.7 V also had an impact in the regions well supplied with hydrogen (hydrogen purges were triggered when the fuel cell voltage dropped from about 0.7 V to 0.5 V). According to our results, Localized and transient hydrogen starvation events may be difficult to detect by considering only the overall fuel cell performance.
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Time Evolution of Local Potentials During PEM Fuel Cell Operation With Dead-Ended Anode
ECS Transactions, 2013Co-Authors: Sofyane Abbou, Jérôme Dillet, Dusan Spernjak, Rangachary Mukundan, Joseph D. Fairweather, Rod L. Borup, Gaël Maranzana, Sophie Didierjean, Olivier LottinAbstract:We present experimental results obtained with a 2D segmented cell with reference electrodes along the gas channels, used to record Local anode and Cathode potentials. Aging protocols consisting of repeated dead-end operation sequences were performed to assess the impact of hydrogen starvation on the Local fuel cell performance. We observed strong Local Cathode potential excursion, as well as non-uniform ECSA losses and performance degradation along the cell area. The damage was more pronounced in the regions suffering the longest from fuel starvation: i.e. close to the exit of the anode compartment.