Fan Zhou, Samuel Simon Araya, I. Grigoras, S. J. Andreasen, S. Kær
Degradation tests of two phosphoric acid (PA) doped polybenzimidazole (PBI) membrane based high temperature polymer electrolyte membrane (HT-PEM) fuel cells were reported in this paper to investigate the effects of start/stop and the presence of methanol in the fuel to the performance degradation. Continuous tests with H2 and simulated reformate which was composed of H2, water steam and methanol as the fuel were performed on both single cells. 12-h-startup/12-h-shutdown dynamic tests were performed on the first single cell with pure dry H2 as the fuel and on the second single cell with simulated reformate as the fuel. Along with the tests electrochemical techniques such as polarization curves and electrochemical impedance spectroscopy (EIS) were employed to study the degradation mechanisms of the fuel cells. Both single cells showed an increase in the performance in the H2 continuous tests, because of a decrease in the oxygen reduction reaction (ORR) kinetic resistance probably due to the redistribution of PA between the membrane and electrodes. EIS measurement of first fuel cell during the start/stop test showed that the mass transfer resistance and ohmic resistance increased which can be attributed to the corrosion of carbon support in the catalyst layer and degradation of the PBI membrane. During the continuous test with simulated reformate as the fuel the ORR kinetic resistance and mass transfer resistance of both single cells increased. The performance of the second single cell experienced a slight decrease during the start/stop test with simulated reformate as the fuel. [DOI: 10.1115/1.4029081]
{"title":"Performance Degradation Tests of Phosphoric Acid Doped Polybenzimidazole Membrane Based High Temperature Polymer Electrolyte Membrane Fuel Cells","authors":"Fan Zhou, Samuel Simon Araya, I. Grigoras, S. J. Andreasen, S. Kær","doi":"10.1115/1.4029081","DOIUrl":"https://doi.org/10.1115/1.4029081","url":null,"abstract":"Degradation tests of two phosphoric acid (PA) doped polybenzimidazole (PBI) membrane based high temperature polymer electrolyte membrane (HT-PEM) fuel cells were reported in this paper to investigate the effects of start/stop and the presence of methanol in the fuel to the performance degradation. Continuous tests with H2 and simulated reformate which was composed of H2, water steam and methanol as the fuel were performed on both single cells. 12-h-startup/12-h-shutdown dynamic tests were performed on the first single cell with pure dry H2 as the fuel and on the second single cell with simulated reformate as the fuel. Along with the tests electrochemical techniques such as polarization curves and electrochemical impedance spectroscopy (EIS) were employed to study the degradation mechanisms of the fuel cells. Both single cells showed an increase in the performance in the H2 continuous tests, because of a decrease in the oxygen reduction reaction (ORR) kinetic resistance probably due to the redistribution of PA between the membrane and electrodes. EIS measurement of first fuel cell during the start/stop test showed that the mass transfer resistance and ohmic resistance increased which can be attributed to the corrosion of carbon support in the catalyst layer and degradation of the PBI membrane. During the continuous test with simulated reformate as the fuel the ORR kinetic resistance and mass transfer resistance of both single cells increased. The performance of the second single cell experienced a slight decrease during the start/stop test with simulated reformate as the fuel. [DOI: 10.1115/1.4029081]","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"021002"},"PeriodicalIF":0.0,"publicationDate":"2015-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4029081","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63487871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pt based materials having high electrocatalytic properties are normally used for the electrodes of the fuel cell. But the cost of the material limits the commercialization of alcoholic fuel cell. Non-Pt based metals and alloys as electrode materials for methyl alcohol fuel cells have been investigated with an aim of finding high electrocatalytic surface property for the faster electrode reactions. Electrodes were fabricated by electrodeposition on pure Al foil, from an electrolyte of Ni, Co, and Fe salts. The optimum condition of electrodeposition was found by a series of experiments, varying the chemistry of the electrolyte, pH, temperature, current, and cell potential. Polarization study of the coated Ni–Co or Ni–Co–Fe alloy on pure Al was found to exhibit high exchange current density, indicating an improved electrocatalytic surface with faster charge– discharge reactions at anode and cathode and low overvoltage. Electrochemical impedance studies on the coated and uncoated surface clearly showed that the polarization resistance and impedance were decreased by Ni–Co or N–Co–Fe coating. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and atomic absorption spectroscopy (AAS) studies confirmed the presence of alloying elements and constituents of the alloy. The morphology of the deposits from scanning electron microscope (SEM) images indicated that the electrode surface was a three-dimensional space which increased the effective surface area for the electrode reactions to take place. [DOI: 10.1115/1.4029063]
{"title":"Electrochemical Characterization of Synthesized Ni–Co and Ni–Co–Fe Electrodes for Methanol Fuel Cell","authors":"S. Paul, Sk. Naimuddin","doi":"10.1115/1.4029063","DOIUrl":"https://doi.org/10.1115/1.4029063","url":null,"abstract":"Pt based materials having high electrocatalytic properties are normally used for the electrodes of the fuel cell. But the cost of the material limits the commercialization of alcoholic fuel cell. Non-Pt based metals and alloys as electrode materials for methyl alcohol fuel cells have been investigated with an aim of finding high electrocatalytic surface property for the faster electrode reactions. Electrodes were fabricated by electrodeposition on pure Al foil, from an electrolyte of Ni, Co, and Fe salts. The optimum condition of electrodeposition was found by a series of experiments, varying the chemistry of the electrolyte, pH, temperature, current, and cell potential. Polarization study of the coated Ni–Co or Ni–Co–Fe alloy on pure Al was found to exhibit high exchange current density, indicating an improved electrocatalytic surface with faster charge– discharge reactions at anode and cathode and low overvoltage. Electrochemical impedance studies on the coated and uncoated surface clearly showed that the polarization resistance and impedance were decreased by Ni–Co or N–Co–Fe coating. X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and atomic absorption spectroscopy (AAS) studies confirmed the presence of alloying elements and constituents of the alloy. The morphology of the deposits from scanning electron microscope (SEM) images indicated that the electrode surface was a three-dimensional space which increased the effective surface area for the electrode reactions to take place. [DOI: 10.1115/1.4029063]","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"011007"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4029063","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63487722","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tien Q. Nguyen, Daniel Minami, Chau Hua, Austin M. Miller, Kevin Tran, John L. Haan
{"title":"Ambient Temperature Operation of a Platinum-Free Direct Formate Fuel Cell","authors":"Tien Q. Nguyen, Daniel Minami, Chau Hua, Austin M. Miller, Kevin Tran, John L. Haan","doi":"10.1115/1.4029072","DOIUrl":"https://doi.org/10.1115/1.4029072","url":null,"abstract":"","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"014501"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4029072","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63487799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effect of biomass gas on the safety performance of a solid oxide fuel cell (SOFC)/micro gas turbine (GT) hybrid system was studied with consideration of the fuel cell working temperature, fuel cell temperature gradient requirement, compressor surge zone, and turbine inlet temperature (TIT). The safety performance of the hybrid system on the design condition and off-design condition was also analyzed. Results show that the hybrid system is good adaptability to low concentrations of biomass gas. The electrical efficiency could reach 50% with different biomass gases and is higher than the other combined power systems that used biomass gas. The wood chip gas (WCG) would make the fuel cell or GT easier overheat than the other three gases. The cotton wood gas (CWG) and corn stalk gas (CSG) are easy to cause the TIT too low or the compressor surge. In the safety zone, considering the hybrid system load adjustment range, the effecting order (from large to small, following is same) is WCG, grape seed gas (GSG), CSG, and CWG. Considering the hybrid system electric efficiency, the effecting order is WCG, GSG, CWG, and CSG.
{"title":"Safety Analysis of a Solid Oxide Fuel Cell/Gas Turbine Hybrid System Fueled With Gasified Biomass","authors":"Xiaojing Lv, Chaohao Lu, Xin-jian Zhu, Y. Weng","doi":"10.1115/1.4029084","DOIUrl":"https://doi.org/10.1115/1.4029084","url":null,"abstract":"The effect of biomass gas on the safety performance of a solid oxide fuel cell (SOFC)/micro gas turbine (GT) hybrid system was studied with consideration of the fuel cell working temperature, fuel cell temperature gradient requirement, compressor surge zone, and turbine inlet temperature (TIT). The safety performance of the hybrid system on the design condition and off-design condition was also analyzed. Results show that the hybrid system is good adaptability to low concentrations of biomass gas. The electrical efficiency could reach 50% with different biomass gases and is higher than the other combined power systems that used biomass gas. The wood chip gas (WCG) would make the fuel cell or GT easier overheat than the other three gases. The cotton wood gas (CWG) and corn stalk gas (CSG) are easy to cause the TIT too low or the compressor surge. In the safety zone, considering the hybrid system load adjustment range, the effecting order (from large to small, following is same) is WCG, grape seed gas (GSG), CSG, and CWG. Considering the hybrid system electric efficiency, the effecting order is WCG, GSG, CWG, and CSG.","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"011008"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4029084","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63487888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. Yuan, Hongrong Xia, Jinyi Hu, Zhaochun Zhang, Yong Tang
Feeding vaporized methanol to the direct methanol fuel cell (DMFC) helps reduce the effects of methanol crossover (MCO) and facilitates the use of high-concentration or neat methanol so as to enhance the energy density of the fuel cell system. This paper reports a novel system design coupling a catalytic combustor with a vapor-feed air-breathing DMFC. The combustor functions as an assistant heat provider to help transform the liquid methanol into vapor phase. The feasibility of this method is experimentally validated. Compared with the traditional electric heating mode, the operation based on this catalytic combustor results in a higher cell performance. Results indicate that the values of methanol concentration and methanol vapor chamber (MVC) temperature both have direct effects on the cell performance, which should be well optimized. As for the operation of the catalytic combustor, it is necessary to optimize the number of capillary wicks and also catalyst loading. In order to fast trigger the combustion reaction, an optimal oxygen feed rate (OFR) must be used. The required amount of oxygen to sustain the reaction can be far lower than that for methanol ignition in the starting stage.
{"title":"Study on a Vapor-Feed Air-Breathing Direct Methanol Fuel Cell Assisted by a Catalytic Combustor","authors":"W. Yuan, Hongrong Xia, Jinyi Hu, Zhaochun Zhang, Yong Tang","doi":"10.1115/1.4029071","DOIUrl":"https://doi.org/10.1115/1.4029071","url":null,"abstract":"Feeding vaporized methanol to the direct methanol fuel cell (DMFC) helps reduce the effects of methanol crossover (MCO) and facilitates the use of high-concentration or neat methanol so as to enhance the energy density of the fuel cell system. This paper reports a novel system design coupling a catalytic combustor with a vapor-feed air-breathing DMFC. The combustor functions as an assistant heat provider to help transform the liquid methanol into vapor phase. The feasibility of this method is experimentally validated. Compared with the traditional electric heating mode, the operation based on this catalytic combustor results in a higher cell performance. Results indicate that the values of methanol concentration and methanol vapor chamber (MVC) temperature both have direct effects on the cell performance, which should be well optimized. As for the operation of the catalytic combustor, it is necessary to optimize the number of capillary wicks and also catalyst loading. In order to fast trigger the combustion reaction, an optimal oxygen feed rate (OFR) must be used. The required amount of oxygen to sustain the reaction can be far lower than that for methanol ignition in the starting stage.","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"6 1","pages":"011002"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4029071","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63487785","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polymer electrolyte membrane (PEM) fuel cells are well suited for automotive applications compared to other types of fuel cells owing to their faster transient response and low-temperature operation. Due to rapid change in loads during automotive applications, study of dynamic behavior is of paramount importance. This study focuses on elucidating the transient response of a PEM fuel cell for specified changes in operating parameters, namely, voltage, pressure, and stoichiometry at the cathode and the anode. Transient numerical simulations are carried out for a single-channel PEM fuel cell to illustrate the response of power as the operating parameters are subjected to specified changes. These parameters are also optimized with an objective to match the power requirements of an automotive drive cycle over a certain period of time.
{"title":"Analysis and Optimization of Transient Response of Polymer Electrolyte Fuel Cells","authors":"A. Verma, R. Pitchumani","doi":"10.1115/1.4028972","DOIUrl":"https://doi.org/10.1115/1.4028972","url":null,"abstract":"Polymer electrolyte membrane (PEM) fuel cells are well suited for automotive applications compared to other types of fuel cells owing to their faster transient response and low-temperature operation. Due to rapid change in loads during automotive applications, study of dynamic behavior is of paramount importance. This study focuses on elucidating the transient response of a PEM fuel cell for specified changes in operating parameters, namely, voltage, pressure, and stoichiometry at the cathode and the anode. Transient numerical simulations are carried out for a single-channel PEM fuel cell to illustrate the response of power as the operating parameters are subjected to specified changes. These parameters are also optimized with an objective to match the power requirements of an automotive drive cycle over a certain period of time.","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"011005"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4028972","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63487995","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The three layers with porous yttria-stabilized zirconia (YSZ) backbone/dense YSZ/porous NiO–YSZ were fabricated by tape-casting process, respectively, then laminated together and co-fired at 1300 °C for 5 h. The cathode material La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) was loaded by infiltrating the precursor of metal ions into porous YSZ backbone. As a result, LSCF nanoparticles with the size of 60–100 nm were uniformly distributed on YSZ backbone. The power density was 1.046 W cm−2 and the polarization resistance was 0.17 Ω cm2 at 800 °C in humidified H2 (3 vol.% H2O). But the stability was not good enough, especially in early operating stage, e.g., 20 h. After that, it showed good stability for the following 70 h operating under a constant voltage of 0.7 V at 750 °C. This is due to the growth and agglomeration of LSCF nanoparticles at early steps, which reduced the three phase boundaries (TPBs).
{"title":"Fabrication and Performance of La0.6Sr0.4Co0.2Fe0.8O3−δ Infiltrated-Yttria-Stabilized Zirconia Cathode on Anode-Supported Solid Oxide Fuel Cell","authors":"D. Tang, Minfang Han, Ziwei Zheng","doi":"10.1115/1.4028947","DOIUrl":"https://doi.org/10.1115/1.4028947","url":null,"abstract":"The three layers with porous yttria-stabilized zirconia (YSZ) backbone/dense YSZ/porous NiO–YSZ were fabricated by tape-casting process, respectively, then laminated together and co-fired at 1300 °C for 5 h. The cathode material La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) was loaded by infiltrating the precursor of metal ions into porous YSZ backbone. As a result, LSCF nanoparticles with the size of 60–100 nm were uniformly distributed on YSZ backbone. The power density was 1.046 W cm−2 and the polarization resistance was 0.17 Ω cm2 at 800 °C in humidified H2 (3 vol.% H2O). But the stability was not good enough, especially in early operating stage, e.g., 20 h. After that, it showed good stability for the following 70 h operating under a constant voltage of 0.7 V at 750 °C. This is due to the growth and agglomeration of LSCF nanoparticles at early steps, which reduced the three phase boundaries (TPBs).","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"011001"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4028947","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63487184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thermal management in the fuel cell component of a direct fired solid oxide fuel cell gas turbine (SOFC/GT) hybrid power system can be improved by effective management and control of the cathode airflow. The disturbances of the cathode airflow were accomplished by diverting air around the fuel cell system through the manipulation of a hot-air bypass valve in open loop experiments, using a hardware-based simulation facility designed and built by the U.S. Department of Energy, National Energy Technology Laboratory (NETL). The dynamic responses of the fuel cell component and hardware component of the hybrid system were studied in this paper.
{"title":"Evaluation of Cathode Air Flow Transients in a SOFC/GT Hybrid System Using Hardware in the Loop Simulation.","authors":"Nana Zhou, Chen Yang, David Tucker","doi":"10.1115/1.4028950","DOIUrl":"https://doi.org/10.1115/1.4028950","url":null,"abstract":"<p><p>Thermal management in the fuel cell component of a direct fired solid oxide fuel cell gas turbine (SOFC/GT) hybrid power system can be improved by effective management and control of the cathode airflow. The disturbances of the cathode airflow were accomplished by diverting air around the fuel cell system through the manipulation of a hot-air bypass valve in open loop experiments, using a hardware-based simulation facility designed and built by the U.S. Department of Energy, National Energy Technology Laboratory (NETL). The dynamic responses of the fuel cell component and hardware component of the hybrid system were studied in this paper.</p>","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"0110031-110037"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4028950","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"33021575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Hydrodynamic and Heat Transfer Effects of Varying Sparger Spacing Within a Column Photobioreactor Using Computational Fluid Dynamics","authors":"G. Bari, T. Suess, G. Anderson, S. Gent","doi":"10.1115/1.4028951","DOIUrl":"https://doi.org/10.1115/1.4028951","url":null,"abstract":"","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"12 1","pages":"011004"},"PeriodicalIF":0.0,"publicationDate":"2015-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4028951","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63487211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Performance Modeling of a Direct Methanol Fuel Cell Fueled With Methanol and Ethanol","authors":"S. Shrestha, Sujith Mohan","doi":"10.1115/1.4028971","DOIUrl":"https://doi.org/10.1115/1.4028971","url":null,"abstract":"","PeriodicalId":15829,"journal":{"name":"Journal of Fuel Cell Science and Technology","volume":"11 1","pages":"061009"},"PeriodicalIF":0.0,"publicationDate":"2014-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1115/1.4028971","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"63487986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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