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Special Issue "Proton Exchange Membrane Fuel Cells (PEMFCs)"

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Electrochemistry".

Deadline for manuscript submissions: closed (31 January 2020).

Special Issue Editors

Prof. Dr. Jean St-Pierre
E-Mail Website
Guest Editor
Hawaii Natural Energy Institute, University of Hawaii at Manoa, Honolulu, HI 96822, USA
Interests: electrochemical energy systems; proton exchange membrane fuel cells including water management, freezing, degradation mechanisms, mathematical modeling, diagnosis and measurement methods, electrocatalysis, pure oxygen operation and reactant stream unit operations (gas separation and fuel reforming catalysts); flow batteries; water electrolyzers
Dr. Shangfeng Du
E-Mail Website
Guest Editor
School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B152TT, UK
Interests: electrochemical engineering; polymer electrolyte fuel cells including electrode design and diagnosis, flow field plate coating, stack design; direct alcohol fuel cells; polymer electrolyte water electrolyzers; zinc-air batteries; nanoparticle characterization

Special Issue Information

Dear Colleagues,

A proton exchange membrane fuel cell (PEMFC) spontaneously produces power, heat and water from the oxygen in the air and a fuel. Hydrogen is preferred as the fuel because it is a renewable fuel if synthesized, for example, by water electrolysis using electricity from renewable energy. Furthermore, fuel cells coupled with hydrogen manufacturing improve resiliency by fulfilling the energy storage needs of electric grids constrained by intermittent renewable energy generation (solar, wind). More specifically, discharge (fuel cell) and recharge (water electrolysis) durations exceeding a few days for power plant ratings below a few megawatts are not accessible to other energy storage technologies. PEMFCs are commercially available for a few applications including cars, forklifts, and generators for homes and backup systems. Improvements in cost, performance and durability are needed to assist commercialization efforts because the technology is not yet mature.

This Special Issue focuses on all PEMFC scientific and technological aspects that decrease cost and increase performance and durability, including novel characterization methods, mathematical models, and accelerated stress tests to gain additional insight, as well as degradation mechanisms, innovative materials and original cell component, cell, stack, and system designs.

Researcher Jean St-Pierre
Dr. Shangfeng Du
Guest Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Proton exchange membrane fuel cell
  • Cost
  • Performance
  • Durability
  • Characterization
  • Model
  • Accelerated stress test
  • Mechanism
  • Material
  • Design

Published Papers (11 papers)

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Research

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Article
Transport and Electrochemical Interface Properties of Ionomers in Low-Pt Loading Catalyst Layers: Effect of Ionomer Equivalent Weight and Relative Humidity
Molecules 2020, 25(15), 3387; https://doi.org/10.3390/molecules25153387 - 26 Jul 2020
Cited by 3 | Viewed by 888
Abstract
Catalyst layer (CL) ionomers control several transport and interfacial phenomena including long-range transport of protons, local transport of oxygen to Pt catalyst, effective utilization of Pt catalyst, electrochemical reaction kinetics and double-layer capacitance. In this work, the variation of these properties, as a [...] Read more.
Catalyst layer (CL) ionomers control several transport and interfacial phenomena including long-range transport of protons, local transport of oxygen to Pt catalyst, effective utilization of Pt catalyst, electrochemical reaction kinetics and double-layer capacitance. In this work, the variation of these properties, as a function of humidity, for CLs made with two ionomers differing in side-chain length and equivalent weight, Nafion-1100 and Aquivion-825, was investigated. This is the first study to examine humidity-dependent oxygen reduction reaction (ORR) kinetics in-situ for CLs with different ionomers. A significant finding is the observation of higher ORR kinetic activity (A/cm2Pt) for the Aquivion-825 CL than for the Nafion-1100 CL. This is attributed to differences in the interfacial protonic concentrations at Pt/ionomer interface in the two CLs. The differences in Pt/ionomer interface is also noted in a higher local oxygen transport resistance for Aquivion-825 CLs compared to Nafion-1100 CLs, consistent with stronger interaction between ionomer and Pt for ionomer with more acid groups. Similar dependency on Pt utilization (ratio of electrochemically active area at any relative humidity (RH) to that at 100% RH) as a function of RH is observed for the two CLs. As expected, strong influence of humidity on proton conduction is observed. Amongst the two, the CL with high equivalent weight ionomer (Nafion-1100) exhibits higher conduction. Full article
(This article belongs to the Special Issue Proton Exchange Membrane Fuel Cells (PEMFCs))
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Article
Development of Porous Pt Electrocatalysts for Oxygen Reduction and Evolution Reactions
Molecules 2020, 25(10), 2398; https://doi.org/10.3390/molecules25102398 - 21 May 2020
Cited by 1 | Viewed by 920
Abstract
Porous Pt electrocatalysts have been developed as an example of carbon-free porous metal catalysts in anticipation of polymer electrolyte membrane (PEM) fuel cells and PEM water electrolyzers through the assembly of the metal precursor and surfactant. In this study, porous Pt was structurally [...] Read more.
Porous Pt electrocatalysts have been developed as an example of carbon-free porous metal catalysts in anticipation of polymer electrolyte membrane (PEM) fuel cells and PEM water electrolyzers through the assembly of the metal precursor and surfactant. In this study, porous Pt was structurally evaluated and found to have a porous structure composed of connected Pt particles. The resulting specific electrochemical surface area (ECSA) of porous Pt was 12.4 m2 g−1, which was higher than that of commercially available Pt black. Accordingly, porous Pt showed higher oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) activity than Pt black. When the activity was compared to that of a common carbon-supported electrocatalyst, Pt/ketjen black (KB), porous Pt showed a comparable ORR current density (2.5 mA cm−2 at 0.9 V for Pt/KB and 2.1 mA cm−2 at 0.9 V for porous Pt), and OER current density (6.8 mA cm−2 at 1.8 V for Pt/KB and 7.0 mA cm−1 at 1.8 V), even though the ECSA of porous Pt was only one-sixth that of Pt/KB. Moreover, it exhibited a higher durability against 1.8 V. In addition, when catalyst layers were spray-printed on the Nafion® membrane, porous Pt displayed more uniform layers in comparison to Pt black, showing an advantage in its usage as a thin layer. Full article
(This article belongs to the Special Issue Proton Exchange Membrane Fuel Cells (PEMFCs))
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Article
Full Parametric Study of the Influence of Ionomer Content, Catalyst Loading and Catalyst Type on Oxygen and Ion Transport in PEM Fuel Cell Catalyst Layers
Molecules 2020, 25(7), 1523; https://doi.org/10.3390/molecules25071523 - 27 Mar 2020
Cited by 4 | Viewed by 1108
Abstract
To advance the technology of polymer electrolyte membrane fuel cells, material development is at the forefront of research. This is especially true for membrane electrode assembly, where the structuring of its various layers has proven to be directly linked to performance increase. In [...] Read more.
To advance the technology of polymer electrolyte membrane fuel cells, material development is at the forefront of research. This is especially true for membrane electrode assembly, where the structuring of its various layers has proven to be directly linked to performance increase. In this study, we investigate the influence of the various ingredients in the cathode catalyst layer, such as ionomer content, catalyst loading and catalyst type, on the oxygen and ion transport using a full parametric analysis. Using two types of catalysts, 40 wt.% Pt/C and 60 wt.% Pt/C with high surface area carbon, the ionomer/carbon content was varied between 0.29–1.67, while varying the Pt loading in the range of 0.05–0.8 mg cm−2. The optimum ionomer content was found to be dependent on the operating point and condition, as well as catalyst loading and type. The data set provided in this work gives a starting point to further understanding of structured catalyst layers. Full article
(This article belongs to the Special Issue Proton Exchange Membrane Fuel Cells (PEMFCs))
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Article
Effect of GDM Pairing on PEMFC Performance in Flow-Through and Dead-Ended Anode Mode
Molecules 2020, 25(6), 1469; https://doi.org/10.3390/molecules25061469 - 24 Mar 2020
Viewed by 1055
Abstract
Asymmetric gas diffusion media (GDM) pairing, which feature distinct GDM at the anode and cathode of the proton electrolyte membrane fuel cell (PEMFC), enhance water management compared to symmetric pairing of GDM (anode and cathode GDM are identical). An asymmetric pairing of Freudenberg [...] Read more.
Asymmetric gas diffusion media (GDM) pairing, which feature distinct GDM at the anode and cathode of the proton electrolyte membrane fuel cell (PEMFC), enhance water management compared to symmetric pairing of GDM (anode and cathode GDM are identical). An asymmetric pairing of Freudenberg GDM (H24C3 at anode and H23C2 at cathode) reduces ohmic resistances by up to 40% and oxygen transport resistances by 14% en route to 25% higher current density in dry gas flows. The asymmetric GDM pairing effectively hydrates the membrane electrode assembly (MEA) while minimizing liquid water saturation in the cathode compared to a commonly used symmetric GDM pairing of SGL 29BC at the anode and cathode. Superior water management observed with asymmetric GDM in flow-through mode is also realized in dead-ended anode (DEA) mode. Compared to the symmetric GDM pairing, the asymmetric GDM pairing with Freudenberg GDM increases cell voltage at all current densities, extends and stabilizes steady-state voltage behavior, slows voltage decay, and vastly reduces the frequency of anode purge events. These results support that the asymmetric Freudenberg GDM combination renders the PEMFC less prone to anode water saturation and performance loss from the anticipated increase in water back-diffusion during DEA mode operation. Full article
(This article belongs to the Special Issue Proton Exchange Membrane Fuel Cells (PEMFCs))
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Article
Automotive Subzero Cold-Start Quasi-Adiabatic Proton Exchange Membrane Fuel Cell Fixture: Design and Validation
Molecules 2020, 25(6), 1410; https://doi.org/10.3390/molecules25061410 - 19 Mar 2020
Cited by 4 | Viewed by 1064
Abstract
Subzero automotive cold-starts of proton exchange membrane fuel cell (PEMFC) stacks require accelerated thermal rises to achieve nominal operating conditions and close-to-instantaneous usable output power. Advances in the material, structure and operational dependence on the balance between the maximum power output and the [...] Read more.
Subzero automotive cold-starts of proton exchange membrane fuel cell (PEMFC) stacks require accelerated thermal rises to achieve nominal operating conditions and close-to-instantaneous usable output power. Advances in the material, structure and operational dependence on the balance between the maximum power output and the electrochemical conversion of hydrogen and oxygen into water requires validation with subzero cold-starts. Herein are presented the design and validation of a quasi-adiabatic PEMFC to enable single-cell evaluation, which would provide a more cost-effective option than stack-level testing. At –20 °C, the operational dependence of the preconditioned water content (3.2 verse 6.2) for a galvanic cold-start (<600 mA cm−2) was counter to that of a laboratory-scale isothermal water fill test (10 mA cm−2). The higher water content resulted in a faster startup to appreciable power output within 0.39 min versus 0.65 min. The water storage capacity, as determined from the isothermal water fill test, was greater, for the lower initial water content of 3.2, than 6.2, 17.4 ± 0.3 mg versus 12.8 ± 0.4 mg, respectively. Potentiostatic cold-starts produced usable power in 0.09 min. The versatility and reproducibility of the single cell quasi-adiabatic fixture avail it to future universal cold-start stack relevant analyzes involving operational parameters and advanced materials, including: applied load, preconditioning, interchanging flow field structures, diffusion media, and catalyst coated membranes. Full article
(This article belongs to the Special Issue Proton Exchange Membrane Fuel Cells (PEMFCs))
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Article
Performance Recovery after Contamination with Nitrogen Dioxide in a PEM Fuel Cell
Molecules 2020, 25(5), 1115; https://doi.org/10.3390/molecules25051115 - 02 Mar 2020
Cited by 1 | Viewed by 937
Abstract
While the market for fuel cell vehicles is increasing, these vehicles will still coexist with combustion engine vehicles on the roads and will be exposed to an environment with significant amounts of contaminants that will decrease the durability of the fuel cell. To [...] Read more.
While the market for fuel cell vehicles is increasing, these vehicles will still coexist with combustion engine vehicles on the roads and will be exposed to an environment with significant amounts of contaminants that will decrease the durability of the fuel cell. To investigate different recovery methods, in this study, a PEM fuel cell was contaminated with 100 ppm of NO2 at the cathode side. The possibility to recover the cell performance was studied by using different airflow rates, different current densities, and by subjecting the cell to successive polarization curves. The results show that the successive polarization curves are the best choice for recovery; it took 35 min to reach full recovery of cell performance, compared to 4.5 h of recovery with pure air at 0.5 A cm−2 and 110 mL min−1. However, the performance recovery at a current density of 0.2 A cm−2 and air flow 275 mL min−1 was done in 66 min, which is also a possible alternative. Additionally, two operation techniques were suggested and compared during 7 h of operation: air recovery and air depletion. The air recovery technique was shown to be a better choice than the air depletion technique. Full article
(This article belongs to the Special Issue Proton Exchange Membrane Fuel Cells (PEMFCs))
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Article
Impact of the Cathode Pt Loading on PEMFC Contamination by Several Airborne Contaminants
Molecules 2020, 25(5), 1060; https://doi.org/10.3390/molecules25051060 - 27 Feb 2020
Cited by 2 | Viewed by 885
Abstract
Proton exchange membrane fuel cells (PEMFCs) with 0.1 and 0.4 mg Pt cm−2 cathode catalyst loadings were separately contaminated with seven organic species: Acetonitrile, acetylene, bromomethane, iso-propanol, methyl methacrylate, naphthalene, and propene. The lower catalyst loading led to larger cell voltage losses [...] Read more.
Proton exchange membrane fuel cells (PEMFCs) with 0.1 and 0.4 mg Pt cm−2 cathode catalyst loadings were separately contaminated with seven organic species: Acetonitrile, acetylene, bromomethane, iso-propanol, methyl methacrylate, naphthalene, and propene. The lower catalyst loading led to larger cell voltage losses at the steady state. Three closely related electrical equivalent circuits were used to fit impedance spectra obtained before, during, and after contamination, which revealed that the cell voltage loss was due to higher kinetic and mass transfer resistances. A significant correlation was not found between the steady-state cell voltage loss and the sum of the kinetic and mass transfer resistance changes. Major increases in research program costs and efforts would be required to find a predictive correlation, which suggests a focus on contamination prevention and recovery measures rather than contamination mechanisms. Full article
(This article belongs to the Special Issue Proton Exchange Membrane Fuel Cells (PEMFCs))
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Article
Development of a Current Collector with a Graphene Thin Film for a Proton Exchange Membrane Fuel Cell Module
Molecules 2020, 25(4), 955; https://doi.org/10.3390/molecules25040955 - 20 Feb 2020
Cited by 2 | Viewed by 906
Abstract
This paper constructs planar-type graphene thin film current collectors for proton exchange membrane fuel cells (PEMFCs). The present planar-type current collector adopts FR-4 as the substrate and coats a copper thin film using thermal evaporation for the electric-conduction layer. A graphene thin film [...] Read more.
This paper constructs planar-type graphene thin film current collectors for proton exchange membrane fuel cells (PEMFCs). The present planar-type current collector adopts FR-4 as the substrate and coats a copper thin film using thermal evaporation for the electric-conduction layer. A graphene thin film is then coated onto the current collector to prevent corrosion due to electrochemical reactions. Three different coating techniques are conducted and compared: Spin coating, RF magnetron sputtering, and screen printing. The corrosion rates and surface resistances are tested and compared for the different coating techniques. Single cell PEMFCs with the developed current collectors are assembled and tested. A PEMFC module with two cells is also designed and constructed. The cell performances are measured to investigate the device feasibility. Full article
(This article belongs to the Special Issue Proton Exchange Membrane Fuel Cells (PEMFCs))
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Article
Tolerance and Recovery of Ultralow-Loaded Platinum Anode Electrodes upon Carbon Monoxide and Hydrogen Sulfide Exposure
Molecules 2019, 24(19), 3514; https://doi.org/10.3390/molecules24193514 - 27 Sep 2019
Cited by 8 | Viewed by 1025
Abstract
The effects of carbon monoxide (CO) and hydrogen sulfide (H2S) in concentrations close to their respective limits in the Hydrogen Quality Standard ISO 14687-2:2012 on the performance of proton exchange membrane fuel cells (PEMFCs) with ultralow-loaded platinum anode catalyst layers (CLs) [...] Read more.
The effects of carbon monoxide (CO) and hydrogen sulfide (H2S) in concentrations close to their respective limits in the Hydrogen Quality Standard ISO 14687-2:2012 on the performance of proton exchange membrane fuel cells (PEMFCs) with ultralow-loaded platinum anode catalyst layers (CLs) were investigated. The anodic loadings were 50, 25, and 15 µg/cm2, which represent the current state-of-the-art, target, and stretch target, respectively, for future automotive PEMFCs. Additionally, the effect of shut-down and start-up (SD/SU) processes on recovery from sulfur poisoning was investigated. CO at an ISO concentration of 0.2 ppm caused severe voltage losses of ~40–50% for ultralow-loaded anode CLs. When H2S was in the fuel, these anode CLs exhibited both a nonlinear decrease in tolerance toward sulfur and an improved self-recovery during shut-down and start-up (SD/SU) processes. This observation was hypothesized to have resulted from the decrease in the ratio between CL thickness and geometric cell area, as interfacial effects of water in the pores increasingly impacted the performance of ultrathin CLs. The results indicate that during the next discussions on the Hydrogen Quality Standard, a reduction in the CO limit could be a reasonable alternative considering future PEMFC anodic loadings, while the H2S limit might not require modification. Full article
(This article belongs to the Special Issue Proton Exchange Membrane Fuel Cells (PEMFCs))
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Article
Optimization of Membrane Electrode Assembly of PEM Fuel Cell by Response Surface Method
Molecules 2019, 24(17), 3097; https://doi.org/10.3390/molecules24173097 - 26 Aug 2019
Cited by 7 | Viewed by 1897
Abstract
The membrane electrode assembly (MEA) plays an important role in the proton exchange membrane fuel cell (PEMFC) performance. Typically, the structure comprises of a polymer electrolyte membrane sandwiched by agglomerate catalyst layers at the anode and cathode. Optimization of various parameters in the [...] Read more.
The membrane electrode assembly (MEA) plays an important role in the proton exchange membrane fuel cell (PEMFC) performance. Typically, the structure comprises of a polymer electrolyte membrane sandwiched by agglomerate catalyst layers at the anode and cathode. Optimization of various parameters in the design of MEA is, thus, essential for reducing cost and material usage, while improving cell performance. In this paper, optimization of MEA is performed using a validated two-phase PEMFC numerical model. Key MEA parameters affecting the performance of a single PEMFC are determined from sensitivity analysis and are optimized using the response surface method (RSM). The optimization is carried out at two different operating voltages. The results show that membrane thickness and membrane protonic conductivity coefficient are the most significant parameters influencing cell performance. Notably, at higher voltage (0.8 V per cell), the current density can be improved by up to 40% while, at a lower voltage (0.6 V per cell), the current density may be doubled. The results presented can be of importance for fuel cell engineers to improve the stack performance and expedite the commercialization. Full article
(This article belongs to the Special Issue Proton Exchange Membrane Fuel Cells (PEMFCs))
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Review

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Review
Composite Polymers Development and Application for Polymer Electrolyte Membrane Technologies—A Review
Molecules 2020, 25(7), 1712; https://doi.org/10.3390/molecules25071712 - 08 Apr 2020
Cited by 11 | Viewed by 1455
Abstract
Nafion membranes are still the dominating material used in the polymer electrolyte membrane (PEM) technologies. They are widely used in several applications thanks to their excellent properties: high proton conductivity and high chemical stability in both oxidation and reduction environment. However, they have [...] Read more.
Nafion membranes are still the dominating material used in the polymer electrolyte membrane (PEM) technologies. They are widely used in several applications thanks to their excellent properties: high proton conductivity and high chemical stability in both oxidation and reduction environment. However, they have several technical challenges: reactants permeability, which results in reduced performance, dependence on water content to perform preventing the operation at higher temperatures or low humidity levels, and chemical degradation. This paper reviews novel composite membranes that have been developed for PEM applications, including direct methanol fuel cells (DMFCs), hydrogen PEM fuel cells (PEMFCs), and water electrolysers (PEMWEs), aiming at overcoming the drawbacks of the commercial Nafion membranes. It provides a broad overview of the Nafion-based membranes, with organic and inorganic fillers, and non-fluorinated membranes available in the literature for which various main properties (proton conductivity, crossover, maximum power density, and thermal stability) are reported. The studies on composite membranes demonstrate that they are suitable for PEM applications and can potentially compete with Nafion membranes in terms of performance and lifetime. Full article
(This article belongs to the Special Issue Proton Exchange Membrane Fuel Cells (PEMFCs))
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