A review on performance degradation of proton exchange membrane fuel cells during startup and shutdown processes: Causes, consequences, and mitigation strategies

Abstract

a b s t r a c tPerformance degradation during startup and shutdown is considered an important issue affecting the durability and lifetime of proton exchange membrane fuel cells (PEMFCs). Due to the high potentials experienced by the cathode during startup and shutdown, the conventional carbon support for the cathode catalyst is prone to oxidation by reacting with oxygen or water. This paper presents an overview of the causes and consequences of performance degradation after frequent startup-shutdown cycles. Mitigation strategies are also summarized, including the use of novel catalyst supports and the application of system strategies to prevent performance degradation in PEMFCs. It is found from the literature review that improvements in catalyst supports to prevent oxidation come at the expense of high cost, and the novel supports developed to date are not sufficient to completely prevent carbon oxidation in fuel cell engines. System strategies, including potential control and reaction gas control, have been developed and applied in fuel cell engines to alleviate or even avoid performance decay. This review aims to provide a clear understanding of the mechanisms related to degradation behaviors during the startup and shutdown processes, thereby helping fuel cell material or system developers in their efforts to prevent performance degradation and prolong the lifetime of PEMFCs.Crown

DEMS and Online Mass Spectrometry Studies of the Carbon Support Corrosion under Various Polymer Electrolyte Membrane Fuel Cell Operating Conditions

“…This is confirmed e.g. in the review of PEMFC degradation processes published by Yu et al 4 The process which is induced by the formation of a hydrogen oxygen front on the anode side upon hydrogen admission after longer standstill can cause potential excursions of the cathode side to potentials between 1.4 and 1.75 V.5 Accordingly, the common tests suites published by US Department of Energy (DoE) and the Fuel Cell Commercialisation Conference of Japan (FCCJ), respectively, comprise both similar accelerated carbon corrosion test protocols based on fast triangular potential cycling to 1.5 V.Carbon corrosion is, however, not the only degradation mechanism occurring in PEMFC. Another important cause of degradation is the loss of platinum surface area by effects like platinum dissolution and * Electrochemical Society Member.…”

“…This is confirmed e.g. in the review of PEMFC degradation processes published by Yu et al 4 The process which is induced by the formation of a hydrogen oxygen front on the anode side upon hydrogen admission after longer standstill can cause potential excursions of the cathode side to potentials between 1.4 and 1.75 V.…”

“…From this results a difference of the integrated carbon mass loss during a stress phase. Carbon mass lost rates were therefore determined by integrating the mass loss over each stress phase and dividing by the stress phase duration of 2000 s. [4] Herein, dm Csp /dt is the average carbon mass loss rate per second during a particular stress phase sp, M C = 12.011 g mol −1 is the atomic mass of carbon. K MS is the mass spectrometer calibration constant defined in Equation 3, I M S 44 (t) is the time dependent MS ion current of fragment m/z = 44 and t sp = 2000 s the duration of the stress phase.…”

Key Factors Affecting the Performance and Durability of Cathode Electrocatalysts in Polymer Electrolyte Fuel Cells Characterized by In Situ Real Time and Spatially Resolved XAFS Techniques

“…The cathode degradation mechanism has also been studied to improve the MEA durability, which becomes more serious issue [1,[36][37][38][39]. Therefore, the nanoscopic spatial place and mechanism of the dissolution and deterioration of the Pt/C cathode electrocatalysts in MEAs should be uncovered to develop next-generation PEFCs with high durability.…”

Screening Bifunctional Pt Based NSTF Catalysts for Durability with the Rotating Disk Electrode: The Effect of Ir and Ru

“…Including oxygen evolution reaction (OER) catalysts with the oxygen reduction reaction (ORR) active Pt, can minimize the extent of the potential transients associated with SUSD events, and thus minimize the damage caused by them. Atanasoski,6 first proposed this materials solution to the RCDM problem, which was in contrast to the many system based approaches (which are listed in the review by Yu et al 7 ). Ir and Ru are the only OER catalysts stable in the acidic conditions of the polymer electrolyte membrane fuel cell (PEMFC), with Ru being the less expensive and more active, but less stable of the two.…”