Effects of Cathode Inlet Relative Humidity on PEMFC Durability during Startup–Shutdown Cycling

Kim, Jae Hong; Jo, Yoo Yeon; Cho, Eun Ae; Jang, Jong Hyun; Kim, Hyoung Juhn; Lim, Tae‐Hoon; Oh, In‐Hwan; Ko, Jae Wook; Son, Ik Jae

doi:10.1149/1.3327888

Cited by 61 publications

(30 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[33][34][35][36] The sensitivity of CCM-Fi to inlet gas relative humidity was investigated. The cell was tested under H 2 /O 2 flow with stoichiometry of 2 at 150 kPa (absolute) .…”

Section: Resultsmentioning

confidence: 99%

Fabrication of High Performing PEMFC Catalyst-Coated Membranes with a Low Cost Air-Assisted Cylindrical Liquid Jets Spraying System

Peng

Omasta

Rigdon

et al. 2016

J. Electrochem. Soc.

View full text Add to dashboard Cite

In this work, a low cost air-assisted cylindrical liquid jets spraying (ACLJS) system was developed to prepare high-performance catalyst-coated membranes (CCMs) for proton exchange membrane fuel cells (PEMFCs). The catalyst ink was flowed from a cylindrical orifice and was atomized by an air stream fed from a coaxial slit and sprayed directly onto the membrane, which was suctioned to a heated aluminum vacuum plate. The CCM pore architecture including size, distribution and volume can be controlled using various flow parameters, and the impact of spraying conditions on electrode structure and PEMFC performance was investigated. CCMs fabricated in the fiber-type break-up regime by ACLJS achieved very high performance during PEMFC testing, with the top-performing cells having a current density greater than 1900 mA/cm 2 at 0.7 V under H 2 /O 2 flows and 700 mA/cm 2 under H 2 /Air at 1.5 bar (absolute) PEMFCs have long been considered to be among the most promising next-generation energy conversion systems for portable devices and transportation vehicles due to their zero or low pollution, high power density and low temperature operation.1-3 However, the widespread commercialization of PEMFCs remains challenged by the high cost of cell assembly and the requirement of durable performance. In the last decade, significant efforts have been launched to make the technology cost competitive and to improve the cell performance by developing new electrocatalysts and lowering the noble metal loading. 4,5 However, the catalyst composition is not the only factor to consider when creating high-performance, low cost PEMFC electrodes.The electrode pore structure plays a critical role in determining PEMFC performance, and it is a direct result of the application method. The electrode porosity and pore size distribution impact reaction kinetics and mass-transport processes, including water management and electron/proton conduction.6-8 Structural optimization can be decisive in reducing performance losses, particularly at low catalyst loading and high current density. 9 In general, the catalyst coated membrane (CCM) method has been found to be superior to the gas diffusion layer (GDL) coating process because CCM fabrication avoids catalyst particles penetrating into the pore network of the GDL, lowering resistance at the interface with the electrolyte. For the CCM method, the catalyst ink can be applied onto the polymer membrane by brushing, screen printing, spraying, reactive spray deposition as well as roll-to-roll methods.6,10-14 Among them, spraying has been commonly employed for CCM fabrication. 11,15,16 However, the effects of spraying conditions on the electrode structure and PEMFC performance are poorly understood in many systems, including the air-assisted cylindrical liquid jets spraying (ACLJS) system.The objective of this work is to investigate the influence of spraying parameters on CCM structure and performance, with a particular focus on the ACLJS system because of its ability to produce very high performance CCMs at...

show abstract

“…[33][34][35][36] The sensitivity of CCM-Fi to inlet gas relative humidity was investigated. The cell was tested under H 2 /O 2 flow with stoichiometry of 2 at 150 kPa (absolute) .…”

Section: Resultsmentioning

confidence: 99%

Fabrication of High Performing PEMFC Catalyst-Coated Membranes with a Low Cost Air-Assisted Cylindrical Liquid Jets Spraying System

Peng

Omasta

Rigdon

et al. 2016

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…As shown in several operating parameters [33][34][35][36][37][38][39] that can have an impact on the degradation rate of PEMFCs under startup and shutdown cycles, including cathode humidity [37,38], cell temperature [33], application of a dummy load [35,36], and gas supply sequences [34]. The hydrogen/air interface during the startup and shutdown processes was mimicked by purging the anode and cathode channels with air after continuous air and hydrogen were supplied.…”

Section: Accelerated Lifetime Tests Under Startup-shutdown Cyclesmentioning

confidence: 99%

“…After the start/stop cycles, the relative number of particles with a diameter ≤2.5 nm declined from 57.20% in a fresh MEA to 1.92%. Cho et al combined the results of cross-sectional SEM and TEM to evaluate Pt/C degradation [33,34,36,38,39,45,59].…”

Section: Agglomeration And/or Dissolution Of Pt Particlesmentioning

confidence: 99%

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

Wang

et al. 2012

Journal of Power Sources

261

150

View full text Add to dashboard Cite

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

show abstract

“…The phenomenon of increasing ion resistance can result from the breaking of side chain or losing of sulfonic acid groups in the catalyst layer or the membrane for one or both of the following reasons: (1) thermal decomposition by local heat spot or (2) attacked by free radical 24. The increasing electron resistance results from carbon corrosion 25. The RH cycling may possibly separate the GDL or catalyst layer away from MEA in certain areas and consequently increase interfacial contact resistance.…”

Section: Resultsmentioning

confidence: 99%

In situ analysis of MEA performance under accelerated degradation testing

Jao

Jung

et al. 2010

Int. J. Energy Res.

View full text Add to dashboard Cite

SUMMARYThe durability of proton exchange membrane fuel cells is one of the key issues hindering their widespread commercialization. This study uses the complex accelerating degradation protocol to investigate the performance decay of a membrane electrode assembly. The complex accelerating protocol includes OCV, RH cycling and load cycling. Linear sweep voltammetry, cyclic voltammetry, AC impedance and polarization curves were used to measure key MEA characteristics. The experimental results in this work revealed that the Nafion s film underwent significant thinning after the 1040th cycle. Moreover, during accelerated degradation testing, the electrochemical surface area decreased and was therefore found to be the main factor affecting the performance decay of the MEA.

show abstract

Effects of Cathode Inlet Relative Humidity on PEMFC Durability during Startup–Shutdown Cycling

Cited by 61 publications

References 30 publications

Fabrication of High Performing PEMFC Catalyst-Coated Membranes with a Low Cost Air-Assisted Cylindrical Liquid Jets Spraying System

Fabrication of High Performing PEMFC Catalyst-Coated Membranes with a Low Cost Air-Assisted Cylindrical Liquid Jets Spraying System

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

In situ analysis of MEA performance under accelerated degradation testing

Contact Info

Product

Resources

About