Degradation of elastomeric gasket materials in PEM fuel cells

Tan, Jinzhu; Chao, Yuh J.; Zee, J. W. Van; Lee, W.K.

doi:10.1016/j.msea.2006.09.098

Cited by 97 publications

(67 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In a recent study [133] the stability of various sealing materials has been tested in a simulated environment at 60 and 80°C. This simulated environment consisted of solutions containing HF and H 2 SO 4 , in two different concentrations.…”

Section: Sealsmentioning

confidence: 99%

Review: Durability and Degradation Issues of PEM Fuel Cell Components

2008

View full text Add to dashboard Cite

Besides cost reduction, durability is the most important issue to be solved before commercialisation of PEM Fuel Cells can be successful. For a fuel cell operating under constant load conditions, at a relative humidity close to 100% and at a temperature of maximum 75 °C, using optimal stack and flow design, the voltage degradation can be as low as 1–2 μV·h. However, the degradation rates can increase by orders of magnitude when conditions include some of the following, i.e. load cycling, start–stop cycles, low humidification or humidification cycling, temperatures of 90 °C or higher and fuel starvation. This review paper aims at assessing the degradation mechanisms of membranes, electrodes, bipolar plates and seals. By collecting long‐term experiments as well, the relative importance of these degradation mechanisms and the operating conditions become apparent.

show abstract

Section: Sealsmentioning

confidence: 99%

Review: Durability and Degradation Issues of PEM Fuel Cell Components

2008

View full text Add to dashboard Cite

show abstract

mentioning

confidence: 99%

“…Many previous studies for contamination [3][4][5][6][7][8][9][10][11][12][13] in PEMFCs have shown the sensitivity of performance to low levels of contamination. For example, cation leachates from gaskets or seals, from NH 3 in the fuel, or from catalyst metals [3][4][5][6][7][8][9] are well known contaminants of the membrane through an ion-exchange mechanism. Catalyst contamination by CO through an adsorption mechanism from feed gas contaminants is so well-known that those studies are too numerous to list here.…”

mentioning

confidence: 99%

An Isothermal Model for Predicting Performance Loss in PEMFCs from Balance of Plant Leachates

Cho

Zee

2014

J. Electrochem. Soc.

View full text Add to dashboard Cite

A model is presented for the contamination of a proton exchange membrane fuel cell (PEMFC), including adsorption onto the Pt catalyst, absorption into the membrane, and ion exchange with ionomeric components. Model predictions for three sources of voltage loss account for the two-dimensional, time-dependent contamination along the channel and into the membrane. The model is developed by considering the well-known concepts of Langmuir adsorption, partition coefficients, plug flow reactors (PFRs), and dimensionless analysis. The phenomena are shown to be controlled by three important dimensionless groups: a Damköhler number for the contamination reaction rate, a capacity ratio, and a coverage ratio for each contamination mechanism. These groups show how to scale ex situ equilibrium data for in situ predictions. The model predictions are shown to be reasonable when compared to in situ experiment data once ex situ data are used to provide reaction and equilibrium parameters. The predictions enable estimation of tolerance limits for leachates according to each mechanism. For typical parameters, the predicted voltage loss in the electrode ionomer by an ion-exchange mechanism shows slower reaction rates but greater performance losses than other mechanisms. Analysis of the potential for commercialization of proton exchange membrane fuel cells (PEMFCs) shows that the cost of balance of plant (BOP) materials can be as much as 30% of the system cost.1 One opportunity to decrease these costs is to use off-the-shelf materials rather than custom-made materials, if leachates from less expensive materials would not affect performance and life-time.2 This loss in performance is related to the contamination of the membrane 3 as well as the electrodes. Many previous studies for contamination [3][4][5][6][7][8][9][10][11][12][13] in PEMFCs have shown the sensitivity of performance to low levels of contamination. For example, cation leachates from gaskets or seals, from NH 3 in the fuel, or from catalyst metals 3-9 are well known contaminants of the membrane through an ion-exchange mechanism. Catalyst contamination by CO through an adsorption mechanism from feed gas contaminants is so well-known that those studies are too numerous to list here. Examples are also known for SO 2 , 10,11 for H 2 S, 12 and even for details of the reverse water-gas shift reaction of CO 2 . 13The fundamental mechanism of contamination from organic contaminants such as aniline, ε-caprolactam, and diaminotoluene (DAT), [14][15][16][17][18] which have been identified as possible system contaminants, have been studied only briefly and recently, and it has been shown that their impact on PEMFC performance depends on their functional groups. For example, the ion-exchange reaction of the amine group in aniline with the Nafion membrane/ionomer causes a decrease in the number of available proton sites, thereby hindering the transport of protons and increasing ohmic losses. Aniline is also adsorbed on the carbonsupported platinum catalyst through interactions betw...

show abstract

“…In spite of these there are reports from all over the world regarding the degradation of silicone rubbers [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19], in various environments for its main structural modifications seen in damaged structure are changes in molecular weight distribution (due to main-chain scission, crosslinking, and end-linking) and production of volatile degradation product. Zhu, et al [6] studied the surface degradation of silicone rubber exposed to corona discharge.…”

Section: Introductionmentioning

confidence: 99%

“…A review on the effects and degradation process of silicones in the environment can be found in Graiver, et al [15]. Tan, et al [16] reported the degradation of elastomeric gasket materials in a simulated fuel cell environment. Despite these possible disadvantages for silicon rubber, limited number of publications concerning degradation of silicon rubber have been made from both academic and industrial institutions.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Damaged Silicon Rubber Hose

Nahar¹,

Zhang²

2011

AJAC

View full text Add to dashboard Cite

Recently, there have been many reports of silicon rubber (SR) hoses becoming brittle in juice factory within one month of purchase. The damage is a new phenomenon, and its cause is unknown. We have collected the damaged hoses attached to UHT sterilizer (ultra-high-temperature) in juice factory and examined them for chemical changes. In addition, we have analyzed the hose-washing chemicals (NaOH and HNO 3 ) that used in juice factory and investigated the effect of NaOH and HNO 3 on a new hose surface in an attempt to establish a probable chemical chain reaction that could attack of the Si-O-Si backbone and cause such degradation. According to WDXRF (Wavelength Dispersive X-Ray Fluorescence), CHNS (Carbon Hydrogen Nitrogen and Sulfur) elemental analysis and FE-SEM photo mapping (Field Emission Scanning Electron Microscope) results, the amount of silicon (Si) and the oxygen (O) concentration were much lower in the damaged hoses than in new SR hose ones. These findings reveal that oxygen-containing silicon-based backbone may leach out from the hose by washing chemicals. As a result, the hoses became brittle after one month of use in juice factory. EDS (Energy-Dispersive-Spectroscopy) peak shows that low concentration of sodium was inserted into the damaged hose surface, due to hose cleaning by NaOH. UV-Vis Spectrometer was used to detect the Si from hose washing chemicals. It was found that the elemental composition of the damaged SR hose changed significantly and both the pH of washing chemicals (NaOH and HNO 3 ) and the exposure UTH temperature have direct effect on the brittleness of the silicon hose in juice factory.

show abstract

Degradation of elastomeric gasket materials in PEM fuel cells

Cited by 97 publications

References 9 publications

Review: Durability and Degradation Issues of PEM Fuel Cell Components

Review: Durability and Degradation Issues of PEM Fuel Cell Components

An Isothermal Model for Predicting Performance Loss in PEMFCs from Balance of Plant Leachates

Analysis of Damaged Silicon Rubber Hose

Contact Info

Product

Resources

About