Effect of System Contaminants on the Performance of a Proton Exchange Membrane Fuel Cell

Abstract

The performance loss and recovery of the fuel cell due to Balance of Plant (BOP) contaminants was identified via a combination of experimental data and a mathematical model. The experiments were designed to study the influence of organic contaminants (e.g. those from BOP materials) on the resistance of the catalyst, ionomer and membrane, and a mathematical model was developed that allowed us to separate these competing resistances from the data collected on an operating fuel cell. For this reason, based on the functional groups, four organic contaminants found in BOP materials, diethylene glycol monoethyl ether (DGMEE), diethylene glycol monoethyl ether acetate (DGMEA), benzyl alcohol (BzOH) and 2,6-diaminotoluene (2,6-DAT) were infused separately to the cathode side of the fuel cell. The cell voltage and high frequency impedance resistance was measured as a function of time. The contaminant feed was then discontinued and voltage recovery was measured. It was determined that compounds with ion exchange properties like 2,6-DAT can cause voltage loss with non-reversible recovery, so this compound was studied in more detail. The degree of voltage loss increased with an increase in concentration, and/or infusion time, and increased with a decrease in catalyst loadings. The major technical challenges for polymer electrolyte membrane fuel cells (PEMFCs) in general are performance, reliability, durability and cost. There is an opportunity to reduce overall system cost by choosing lower cost balance of plant (BOP) materials for PEMFC systems. However, choosing any new system BOP material (e.g., assembly aids, structural plastics, and hoses) without compromising function, fuel cell performance, or life requires understanding the effects of the contaminants that leach from these materials. The contaminants in a fuel cell system originate from the fuel, air, and the different component materials used in construction.Previous studies 1-28 have reported on the effect of contamination on PEMFCs by impurities found in the fuel, fuel-cell components, or the external environment such as carbon monoxide (CO), 8,9 26 It has been demonstrated that even trace amounts of impurities can severely poison the anode, membrane, and cathode, particularly at low-temperature operation.4 These contaminants impact PEMFC performance by hindering kinetics (e.g. CO and H 2 S) or reducing membrane conductivity (e.g. NH 3 and metal cations). 8,18,19 Several models are available that capture kinetic [24][25][26] and ohmic overpotentials [18][19][20]27,28 during the contamination and recovery studies.Although there has been a lot of research on contamination caused by fuel and air side impurities, the effect of contamination originating from system components have only recently been briefly studied. 29-35These results showed that despite the contamination caused by fuel and air side impurities that can effect only the catalyst (e.g., CO) or the membrane (e.g. metal cations), organic contaminants (e.g., those from BOP materials) can have severe effect...

Double Perovskite LaFe1−xNixO3 Coated with Sea Urchin-like Gold Nanoparticles Using Electrophoresis as the Photoelectrochemical Electrode to Enhance H2 Production via Surface Plasmon Resonance Effect

“…The reason for this is that the resistance of 1-butanol is higher than the resistance of ethanol, as 1-butanol has four carbon atoms in one molecule. The higher resistance results in a loss of conductivity (ohmic loss) and proton activity (kinetic loss) [41]. Equation ( 5) [42] is used to calculate the real production, where η is the H 2 generation efficiency, P s is the light power (1000 W/m 2 ), A is the area (10 −4 m 2 for all samples), 237.1 × 10 3 is the energy required for forming one mol of H 2 , and 2.0158 is the molecular weight of one mol of H 2 .…”

Poisoning Effects of H2S, CS2, and COS on Hydrogen Oxidation Reaction over Pt/C Catalysts

“…However, some sulfur-containing impurities are inevitably generated in the productive process and can do a great harm to the fuel cells. It is revealed that sulfur species could poison the Pt catalyst with a significant loss of cell power. − The poisonous effect is so serious that the standard of ISO 14687, which describes the product specification of hydrogen fuel quality in PEMFCs, limits the content of sulfur compounds in hydrogen fuel to an extremely low value of 4 ppb. Therefore, it is of great significance to understand the influence of trace sulfur-containing impurities on the Pt catalyst to improve the durability of hydrogen fuel cells.…”

Impact of the Cathode Pt Loading on PEMFC Contamination by Several Airborne Contaminants

“…The authors also refer to 10 ppb SO 2 data obtained by another group that showed more severe fuel cell damage with a catalyst loading decrease from 0.4 to 0.3 mg Pt cm −2 . In contrast, the effect of 2,6-diaminotoluene, a species that leaches out of the fuel cell system balance of plant materials, was more impactful after the Pt catalyst loading was lowered from 0.4 to 0.1 mg Pt cm −2 [20]. In comparison to the anode, the higher cathode potential is expected to affect the contamination mechanism with, for example, a different Pt surface charge, altered contaminant adsorbates and reaction intermediates, catalyst coverage, and cell voltage loss.…”

“…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.Molecules 2020, 25, 1060 2 of 15 focusing on the cathode catalyst loading effect were found [19,20]. However, contamination data in [19] are not directly comparable because both the catalyst layer design and catalyst loading were concurrently altered.…”

“…Molecules 2020, 25, 1060 2 of 15 focusing on the cathode catalyst loading effect were found [19,20]. However, contamination data in [19] are not directly comparable because both the catalyst layer design and catalyst loading were concurrently altered.…”