Durability PFSA membranes

Endoh E (2008) Development of highly durable PFSA membrane and MEA for PEMFC under high temperature and low humidity conditions. ECS Trans 16 1229-1240... 

Endoh E (2009) Highly durable PFSA membranes. In Vielstich W, Gasteiger HA, Yokokawa H (eds) Handbook of fuel cells - advances in electrocatalysis, materials, diagnostics, and durability, vol 5. Wiley, Chichester, pp 361-374... 

The ideal additive would enhance proton conductivity and stabihty. One demonstration of this was in a composite PFSA membrane using Pt nanoparticles supported on titania or silica [63]. The composite membranes when employed in MEAs demonstrated unhumidifled fuel cell performance comparable to that of a similar humidified fuel cell. Whether adding Pt to the membrane will help durability or hurt it is still a matter of some debate [64, 65]. Unfortunately, it is not commercially feasible at this time to add additional Pt to the MEA and so this approach while novel is not practical. The HPAs are known peroxide decomposition catalysts and so these inorganic oxides have been demonstrated to improve performance and decompose peroxide in fuel cells and if they could be immobilized would present a practical solution to this problem [66]. 

The scientific community has made great progress in increasing the durability of polymer electrolyte membrane fuel cell (PEMFC) systems, but durability must further increase before we can consider fuel cells economically viable [1]. As durability increases, new modes of fuel cell contamination and failure are exposed. We expect state of the art PEMFC systems to run for thousands of hours. This means that each sulfonate group in typical per-fluorosulfonic acid (PFSA) membranes used in today s PEMFC systems will associate with several million protons over the lifetime of the systems. Even if other cations replace only a small fraction of the protons entering the electrolyte membrane, these contaminant cations can build up in the system and degrade the fuel cell system performance over time. 

Endoh et al. (2009) and Endoh (2006, 2008) have developed new polymer composites (NPCs), which have a highly durable PFSA base under high-temperature and low-humidity conditions. The NPC membrane showed excellent stability that approximated 3000 h in an open-circuit voltage (OCV) test at 120°C and 18% relative humidity, and the continuous operation using an NPC membrane could be... 

During operation of PEMFCs, fluoride ions, sulfate ions, and low molecular weight perfluorosulfonic acid are found in drain water. Direct gas mass spectroscopy of the cathode outlet gas indicated the formation of HE, H O, CO, SO, SO, H SO, and HjSOj in OCV durability tests (Teranishi et al. 2006). PFSA membranes contain no a-hyi"ogens, which are vulnerable to radical attacks, and hence the membranes would be stable against radical attacks (Mitov et al. 2005) if they have perfectly... 

PFSA membrane is by far the most studied proton electrolyte for PEMFC. There are three advantages to the use of PFSA membranes in PEMFCs. First, due to PTEE-based backbone, PFSA membranes are relatively strong and stable in both oxidative and reductive environments. In fact, durability of 60,000 h has been reported." Second, the proton conductivity achieved in PFSA manbrane can be as high as 0.13 S/cm at 75°C and 100% relative humidityA ceU resistance is as low as 0.05 cm for a 100 pm thick membrane with voltage loss of only 50 mV at 1 A/cm. " Third, PFSA has relatively good mechanical properties. For Nafion... 

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