Advanced materials for improved PEMFC performance and life

Curtin, Dennis E.; Lousenberg, Robert D.; Henry, Timothy J.; Tangeman, Paul C.; Tisack, Monica E.

doi:10.1016/b978-008044696-7/50053-2

Cited by 49 publications

(89 citation statements)

References 3 publications

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“…So, in order to demonstrate our fuel cell durability framework in the present work, we chose the relative humidity of 100% in both anode and cathode channels. changing the membrane structural properties [30]. Since, the present study assumes a cross-flow configuration (fluid flow direction marked by arrows in the figure), one can also observe that the highest water vapor presence is consistently near the inlet section of anode and outlet of the cathode.…”

Section: Single-cell Performancementioning

confidence: 82%

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A multi-timescale modeling methodology for PEMFC performance and durability in a virtual fuel cell car

Mayur

Strahl

Husar

et al. 2015

International Journal of Hydrogen Energy

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Abstract.The durability of polymer electrolyte membrane fuel cells (PEMFC) is governed by a nonlinear coupling between system demand, component behavior, and physicochemical degradation mechanisms, occurring on timescales from the sub-second to the thousand-hour. We present a simulation methodology for assessing performance and durability of a PEMFC under automotive driving cycles. The simulation framework consists of (a) a fuel cell car model converting velocity to cell power demand, (b) a 2D multiphysics cell model, (c) a flexible degradation library template that can accommodate physically-based component-wise degradation mechanisms, and (d) a time-upscaling methodology for extrapolating degradation during a representative load cycle to multiple cycles. The computational framework describes three different time scales, (1) sub-second timescale of electrochemistry, (2) minute-timescale of driving cycles, and (3) thousand-hour-timescale of cell ageing. We demonstrate an exemplary PEMFC durability analysis due to membrane degradation under a highly transient loading of the New European Driving Cycle (NEDC).

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Section: Single-cell Performancementioning

confidence: 82%

“…A relatively persistent presence of water vapor means that those locations in the membrane are exposed to less cycling and hence less mechanical damage occurs in those locations. But at the same time, they expose the membrane to a more steady chemical damage [30]. …”

Section: Single-cell Performancementioning

confidence: 99%

A multi-timescale modeling methodology for PEMFC performance and durability in a virtual fuel cell car

Mayur

Strahl

Husar

et al. 2015

International Journal of Hydrogen Energy

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“…Nafion TM /PTA (phosphotungstic acid) operating on hydrogen/oxygen at ambient pressure achieve 0.6 V at 180 mA/cm 2 for an operating temperature of 120 • C [35], and Nafion TM -Teflon Zr(HPO 4 ) operating on hydrogen/oxygen at 120 • C achieved 0.6 V at 400 mA/cm 2 [32]. While performance is significantly lower than PEM Nafion TM performance when operated at 80 • C and ambient pressure with saturated reactants, it is roughly equivalent to the performance of Nafion TM /phosphoric acid [36], however there are little to no data on the durability of these membranes at fuel-cell operating conditions Durability of the membrane has been studied by numerous researchers [37][38][39][40][41]. Degradation of Nafion TM has been separated into the following three mechanisms: chemical, thermal, and mechanical.…”

Section: High Temperature Polymer Electrolyte Membranesmentioning

confidence: 99%

Catalyst, Membrane, Free Electrolyte Challenges, and Pathways to Resolutions in High Temperature Polymer Electrolyte Membrane Fuel Cells

2017

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High temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) are being studied due to a number of benefits offered versus their low temperature counterparts, including co-generation of heat and power, high tolerance to fuel impurities, and simpler system design. Approximately 90% of the literature on HT-PEM is related to the electrolyte and, for the most part, these electrolytes all use free phosphoric acid, or similar free acid, as the ion conductor. A major issue with using phosphoric acid based electrolytes is the free acid in the electrodes. The presence of the acid on the catalyst sites leads to poor oxygen activity, low solubility/diffusion, and can block electrochemical sites through phosphate adsorption. This review will focus on these issues and the steps that have been taken to alleviate these obstacles. The intention is this review may then serve as a tool for finding a solution path in the community.

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“…In another study, 38 FTIR studies revealed trace amount of R-SO 2 F or S-O-S formation when Nafion™ was degraded by H 2 O 2 /Fe(II) solutions; such reagents are commonly known as Fenton's reagent, and are widely used to generate hydroxyl and hydroperoxyl radicals. 39 The authors also commented that the side chains were decomposed more easily than the main chain, based on the 19 41 . As shown in Figure 20, the degradation process starts from the carboxylic acid end groups (-COOH) that may be present in small concentrations.…”

Section: Model Compound and Membrane Chemical Durability Studiesmentioning

confidence: 99%

Final Report - MEA and Stack Durability for PEM Fuel Cells

Yandrasits¹

2008

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The principal objectives of this program were to develop membrane electrode assemblies (MEAs) and systems that are durable up to 40,000 hours under stationary power conditions and at the same time can be manufacture in high volume, commercial processes.All MEA materials, process development work was carried out by 3M Co., at its St. Paul, MN, 3M Center campus and its Menomonie, WI, production plant. The 3M team included primarily members from the Fuel Cell Components Program, but significant assistance was received over Executive SummaryProton exchange membrane fuel cells are expected to change the landscape of power generation over the next ten years. For this to be realized one of the most significant challenges for stationary systems is lifetime, where 40,000 hours of operation with less than 10% decay is desired. This project conducted fundamental studies on the durability of membrane electrode assemblies (MEAs) and fuel cell stack systems with the expectation that knowledge gained from this project will be applied toward the design and manufacture of MEAs and stack systems to meet DOE's 2010 stationary fuel cell stack systems targets.The focus of this project was proton exchange membrane (PEM) fuel cell durabilityunderstanding the issues that limit MEA and fuel cell system lifetime, developing mitigation strategies to address the lifetime issues and demonstration of the effectiveness of the mitigation strategies by system testing. To that end, several discoveries were made that contributed to the fundamental understanding of MEA degradation mechanisms. (1) The classically held belief that membrane degradation is solely due to polymer end-group "unzipping" is incorrect; there are other functional groups present in the ionomer that are susceptible to chemical attack. (2) The rate of membrane degradation can be greatly slowed or possibly eliminated through the use of additives that scavenge peroxide or peroxyl radicals. (3) Characterization of gas diffusion layer (GDL) using dry gases is incorrect due to the fact that fuel cells operate utilizing humidified gases. The proper characterization method involves using wet gas streams and measuring capillary pressure as demonstrated in this project. (4) Not all Platinum on carbon catalysts are created equally -the major factor impacting catalyst durability is the type of carbon used as the support. (5) System operating conditions have a significant impact of lifetime -the lifetime was increased by an order of magnitude by changing the load profile while all other variables remain the same. (6) Through the use of statistical lifetime analysis methods, it is possible to develop new MEAs with predicted durability approaching the DOE 2010 targets. (7) A segmented cell was developed that extend the resolution from ~ 40 to 121 segments for a 50cm2 active area single cell which allowed for more precise investigation of the local phenomena in a operating fuel cell. (8) The single segmented cell concept was extended to a fuel size stack to allow the first of its kind moni...

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Advanced materials for improved PEMFC performance and life

Cited by 49 publications

References 3 publications

A multi-timescale modeling methodology for PEMFC performance and durability in a virtual fuel cell car

A multi-timescale modeling methodology for PEMFC performance and durability in a virtual fuel cell car

Catalyst, Membrane, Free Electrolyte Challenges, and Pathways to Resolutions in High Temperature Polymer Electrolyte Membrane Fuel Cells

Final Report - MEA and Stack Durability for PEM Fuel Cells

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