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Special Issue "Hydrogen Energy and Fuel Cells"

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A special issue of Energies (ISSN 1996-1073).

Deadline for manuscript submissions: closed (31 July 2012)

Special Issue Editor

Guest Editor
Dr. Nico Hotz

Thermodynamics and Sustainable Energy Lab, Department of Mechanical Engineering and Material Science, Pratt School of Engineering, Duke University, Box 90300 Hudson Hall, Durham, NC 27708-0300, USA
Website | E-Mail
Phone: +1 919 660 5118
Interests: hydrogen and fuel cell systems; exergy analysis of complex systems; renewable energies; thermodynamics; heat and mass transfer; micro- and nano-technology; solar energy; alternative fuels; biofuels; fuel processing

Special Issue Information

Dear Colleagues,

Hydrogen is a highly promising energy carrier, offering advantages of a clean and environmentally friendly fuel with a high energy density per mass and without releasing pollutants to the environment through the exhaust gas. Especially when used in fuel cells, hydrogen is a very efficient energy carrier and could help solving some of the world's energy challenges. Fuel cells can directly convert chemically stored energy to electrical and thermal energy by electrochemically oxidizing fuels, ideally hydrogen. This special issue will combine experimental and numerical publications on various aspects of a future hydrogen economy and fuel cells, namely studies and reviews on hydrogen generation, hydrogen storage, and hydrogen utilization on the one hand side and low-, intermediate- and high-temperature fuel cells on the other hand. All energy sources for hydrogen generation, all types of applications such as stationary, portable, or automotive, and all types of fuel cells are of interest for this special issue.

Dr. Nico Hotz
Guest Editor

Keywords

  • hydrogen generation
  • hydrogen storage
  • hydrogen utilization
  • low-temperature fuel cells
  • intermediate-temperature fuel cells
  • high-temperature fuel cells

Published Papers (7 papers)

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Research

Open AccessArticle Electrodeposition of a Au-Dy2O3 Composite Solid Oxide Fuel Cell Catalyst from Eutectic Urea/Choline Chloride Ionic Liquid
Energies 2012, 5(12), 5363-5371; doi:10.3390/en5125363
Received: 15 August 2012 / Revised: 20 October 2012 / Accepted: 7 December 2012 / Published: 19 December 2012
Cited by 2 | PDF Full-text (1612 KB) | HTML Full-text | XML Full-text
Abstract
In this research we have fabricated and tested Au/Dy2O3 composites for applications as Solid Oxide Fuel Cell (SOFC) electrocatalysts. The material was obtained by a process involving electrodeposition of a Au-Dy alloy from a urea/choline chloride ionic liquid electrolyte, followed
[...] Read more.
In this research we have fabricated and tested Au/Dy2O3 composites for applications as Solid Oxide Fuel Cell (SOFC) electrocatalysts. The material was obtained by a process involving electrodeposition of a Au-Dy alloy from a urea/choline chloride ionic liquid electrolyte, followed by selective oxidation of Dy to Dy2O3 in air at high temperature. The electrochemical kinetics of the electrodeposition bath were studied by cyclic voltammetry, whence optimal electrodeposition conditions were identified. The heat-treated material was characterised from the morphological (scanning electron microscopy), compositional (X-ray fluorescence spectroscopy) and structural (X-ray diffractometry) points of view. The electrocatalytic activity towards H2 oxidation and O2 reduction was tested at 650 °C by electrochemical impedance spectrometry. Our composite electrodes exhibit an anodic activity that compares favourably with the only literature result available at the time of this writing for Dy2O3 and an even better cathodic performance. Full article
(This article belongs to the Special Issue Hydrogen Energy and Fuel Cells)
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Open AccessArticle Experimental Characterization of the Poisoning Effects of Methanol-Based Reformate Impurities on a PBI-Based High Temperature PEM Fuel Cell
Energies 2012, 5(11), 4251-4267; doi:10.3390/en5114251
Received: 3 August 2012 / Revised: 9 October 2012 / Accepted: 18 October 2012 / Published: 24 October 2012
Cited by 12 | PDF Full-text (1349 KB) | HTML Full-text | XML Full-text
Abstract
In this work the effects of reformate gas impurities on a H3PO4-doped polybenzimidazole (PBI) membrane-based high temperature proton exchange membrane fuel cell (HT-PEMFC) are studied. A unit cell assembly with a BASF Celtec®-P2100 high temperature membrane electrode
[...] Read more.
In this work the effects of reformate gas impurities on a H3PO4-doped polybenzimidazole (PBI) membrane-based high temperature proton exchange membrane fuel cell (HT-PEMFC) are studied. A unit cell assembly with a BASF Celtec®-P2100 high temperature membrane electrode assembly (MEA) of 45 cm2 active surface area is investigated by means of impedance spectroscopy. The concentrations in the anode feed gas of all impurities, unconverted methanol-water vapor mixture, CO and CO2 were varied along with current density according to a multilevel factorial design of experiments. Results show that all the impurities degrade the performance, with CO being the most degrading agent and CO2 the least. The factorial analysis shows that there is interdependence among the effects of the different factors considered. This interdependence suggests, for example, that tolerances to concentrations of CO above 2% may be compromised by the presence in the anode feed of CO2. Methanol has a poisoning effect on the fuel cell at all the tested feed ratios, and the performance drop is found to be proportional to the amount of methanol in feed gas. The effects are more pronounced when other impurities are also present in the feed gas, especially at higher methanol concentrations. Full article
(This article belongs to the Special Issue Hydrogen Energy and Fuel Cells)
Open AccessArticle Exergy Analysis of an Intermediate Temperature Solid Oxide Fuel Cell-Gas Turbine Hybrid System Fed with Ethanol
Energies 2012, 5(11), 4268-4287; doi:10.3390/en5114268
Received: 10 July 2012 / Revised: 24 September 2012 / Accepted: 18 October 2012 / Published: 24 October 2012
Cited by 4 | PDF Full-text (1156 KB) | HTML Full-text | XML Full-text
Abstract
In the present work, an ethanol fed Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) system has been parametrically analyzed in terms of exergy and compared with a single SOFC system. The solid oxide fuel cell was fed with hydrogen produced from ethanol steam reforming.
[...] Read more.
In the present work, an ethanol fed Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) system has been parametrically analyzed in terms of exergy and compared with a single SOFC system. The solid oxide fuel cell was fed with hydrogen produced from ethanol steam reforming. The hydrogen utilization factor values were kept between 0.7 and 1. The SOFC’s Current-Volt performance was considered in the range of 0.1–3 A/cm2 at 0.9–0.3 V, respectively, and at the intermediate operating temperatures of 550 and 600 °C, respectively. The curves used represent experimental results obtained from the available bibliography. Results indicated that for low current density values the single SOFC system prevails over the SOFC-GT hybrid system in terms of exergy efficiency, while at higher current density values the latter is more efficient. It was found that as the value of the utilization factor increases the SOFC system becomes more efficient than the SOFC-GT system over a wider range of current density values. It was also revealed that at high current density values the increase of SOFC operation temperature leads in both cases to higher system efficiency values. Full article
(This article belongs to the Special Issue Hydrogen Energy and Fuel Cells)
Open AccessArticle A Revisit to the Hydrogen Desorption/Absorption Behaviors of LiAlH4/LiBH4: Effects of Catalysts
Energies 2012, 5(9), 3691-3700; doi:10.3390/en5093691
Received: 31 July 2012 / Revised: 5 September 2012 / Accepted: 19 September 2012 / Published: 21 September 2012
Cited by 3 | PDF Full-text (296 KB) | HTML Full-text | XML Full-text
Abstract
The hydrogen desorption/absorption behaviors of LiAlH4/LiBH4 with a focus on the effects of catalysts, namely TiCl3, TiO2, VCl3, and ZrCl4, were investigated using a thermal-volumetric apparatus. The hydrogen desorption was performed from
[...] Read more.
The hydrogen desorption/absorption behaviors of LiAlH4/LiBH4 with a focus on the effects of catalysts, namely TiCl3, TiO2, VCl3, and ZrCl4, were investigated using a thermal-volumetric apparatus. The hydrogen desorption was performed from room temperature to 300 °C with a heating rate of 2 °C min−1. The LiAlH4–LiBH4 mixture with a molar ratio of 2:1 decomposed between 100 and 220 °C, and the hydrogen desorption capacity reached up to 6.6 wt %. Doping 1 mol % of a catalyst to the mixture resulted in the two-step decomposition and a decrease in the hydrogen desorption temperature. All the doped samples provided lower amountz of desorbed hydrogen than that obtained from the undoped one. No hydrogen absorption was observed under 8.5 MPa of hydrogen pressure and 300 °C for 6 h. Despite the fact each of the catalysts may affect the hydrogen storage behaviors of the mixture differently, none resulted in a change in the sample reversibility. Full article
(This article belongs to the Special Issue Hydrogen Energy and Fuel Cells)
Open AccessArticle An Equivalent Electrical Circuit Model of Proton Exchange Membrane Fuel Cells Based on Mathematical Modelling
Energies 2012, 5(8), 2724-2744; doi:10.3390/en5082724
Received: 5 April 2012 / Revised: 16 July 2012 / Accepted: 18 July 2012 / Published: 27 July 2012
Cited by 11 | PDF Full-text (722 KB) | HTML Full-text | XML Full-text
Abstract
Many of the Proton Exchange Membrane Fuel Cell (PEMFC) models proposed in the literature consist of mathematical equations. However, they are not adequately practical for simulating power systems. The proposed model takes into account phenomena such as activation polarization, ohmic polarization, double layer
[...] Read more.
Many of the Proton Exchange Membrane Fuel Cell (PEMFC) models proposed in the literature consist of mathematical equations. However, they are not adequately practical for simulating power systems. The proposed model takes into account phenomena such as activation polarization, ohmic polarization, double layer capacitance and mass transport effects present in a PEM fuel cell. Using electrical analogies and a mathematical modeling of PEMFC, the circuit model is established. To evaluate the effectiveness of the circuit model, its static and dynamic performances under load step changes are simulated and compared to the numerical results obtained by solving the mathematical model. Finally, the applicability of our model is demonstrated by simulating a practical system. Full article
(This article belongs to the Special Issue Hydrogen Energy and Fuel Cells)
Open AccessArticle Dynamic Modeling of Anode Function in Enzyme-Based Biofuel Cells Using High Mediator Concentration
Energies 2012, 5(7), 2524-2544; doi:10.3390/en5072524
Received: 21 March 2012 / Revised: 5 June 2012 / Accepted: 27 June 2012 / Published: 17 July 2012
Cited by 2 | PDF Full-text (1647 KB) | HTML Full-text | XML Full-text
Abstract
The working principle of enzyme-based biofuel cells (EBFCs) is the same as that of conventional fuel cells. In an EBFC system, the electricity-production process is very intricate. Analysis requires a mathematical model that can adequately describe the EBFC and predict its performance. This
[...] Read more.
The working principle of enzyme-based biofuel cells (EBFCs) is the same as that of conventional fuel cells. In an EBFC system, the electricity-production process is very intricate. Analysis requires a mathematical model that can adequately describe the EBFC and predict its performance. This paper develops a dynamic model simulating the discharge performance of the anode for which supported glucose oxidase and mediator immobilize in the EBFC. The dynamic transport behavior of substrate, redox state (ROS) of enzyme, enzyme-substrate complex, and the mediator creates different potential changes inside the anode. The potential-step method illustrates the dynamic phenomena of substrate diffusion, ROS of enzyme, production of enzyme-substrate complex, and reduction of the mediator with different potential changes. Full article
(This article belongs to the Special Issue Hydrogen Energy and Fuel Cells)
Open AccessArticle Reactivation System for Proton-Exchange Membrane Fuel-Cells
Energies 2012, 5(7), 2404-2423; doi:10.3390/en5072404
Received: 28 March 2012 / Revised: 27 June 2012 / Accepted: 9 July 2012 / Published: 13 July 2012
PDF Full-text (789 KB) | HTML Full-text | XML Full-text
Abstract
In recent years, Proton-Exchange Membrane Fuel Cells (PEMFCs) have been the focus of very intensive researches. Manufacturers of these alternative power sources propose a rejuvenation sequence after the FC has been operating at high power for a certain period of time. These rejuvenation
[...] Read more.
In recent years, Proton-Exchange Membrane Fuel Cells (PEMFCs) have been the focus of very intensive researches. Manufacturers of these alternative power sources propose a rejuvenation sequence after the FC has been operating at high power for a certain period of time. These rejuvenation methods could be not appropriate for the reactivation of the FC when it has been out of operation for a long period of time or after it has been repaired. Since the developed reactivation system monitors temperature, current, and the cell voltages of the stack, it could be also useful for the diagnostic and repairing processes. The limited number of published contributions suggests that systems developing reactivation techniques are an open research field. In this paper, an automated system for reactivating PEMFCs and results of experimental testing are presented. Full article
(This article belongs to the Special Issue Hydrogen Energy and Fuel Cells)
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