Durability of Polymer Electrolyte Fuel Cells

Stability challenges of carbon-supported Pt-nanoalloys as fuel cell oxygen reduction reaction electrocatalysts

“…Supplied at the anode side of the PEMFC, hydrogen is oxidised and the formed protons travel through the membrane to the cathode side where they react with oxygen from the air creating electricity and water as the only by-product. 9 However, these reactions need a catalyst, namely platinum (Pt) supported on the high-surface-area-carbons (HSACs) in the form of nanoparticles (NPs) (Pt/C). This nanocomposite was proven to be the best option for catalysis of both the anodic hydrogen oxidation reaction (HOR) as well as the cathodic oxygen reduction reaction (ORR).…”

On the evolution of sulfonated polyphenylenes as proton exchange membranes for fuel cells

“…Related to mechanical durability that may be enhanced by reinforcement, is chemical durability, which is put to the test in the presence of H 2 /O 2 fuel cells because the electrocatalyst promotes the formation of H•, HO•, and HOO• radicals, 211,[226][227][228] which are the primary sources of oxidative degradation. 20,228 In commercial fuel cells, degradation of PFSA PEMs is slowed by incorporation of Ce 3+ ions as an antioxidant which neutralizes reactive oxidative radical species. 211,[229][230][231] The Ce 4+ product is re-reduced through a secondary reaction with a hydroperoxyl radical (HOO•) or with H 2 O 2 , regenerating Ce 3+ ions.…”

“…11,18,19 Particular emphasis was placed on aromatic polymer backbones due to the inherent thermochemical resilience associated with sp 2 linkages (aryl-aryl and aryl-heteroatom) compared to labile sp 3 -based linkages (methylene and methenyl) found in early sulfonated polystyrene research. 20,21 Diverse synthetic strategies not limited by perfluorinated reagents led to numerous classes of proton-conducting sulfonated polyarylenes with differing backbone architectures: poly(arylene ether ketone)s, 11,22,14 poly(arylene ether sulfone)s, 11,22,23,24 poly(benzimidazole)s, 11,14,25 poly(arylene sulfone sulfide)s, 26,18,27,28 , and poly(phenylene)s. 29,30,31,32 A persistent criticism of hydrocarbon-based polymer membranes, however, is that they lack the oxidative stability of their PFSA counterparts; research into 4 | P a g e hydrocarbon-based PEMS eventually dwindled, caused in-part by the emerging interest and available funding for the discovery of anion exchange membranes.…”

Current State and Future Prospects for Electrochemical Energy Storage and Conversion Systems

“…Furthermore, various components of the fuel cell, particularly the membrane electrode assembly (MEA), suffer degradation during long term operation [159]. In general, the typical expected lifetime of a PEMFC is around 2500 hrs, which is well below the required life expectancy of 5000 hrs and 40,000 hrs for transportation and stationary applications, respectively [155,160]. Cost is another major impediment towards commercialisation of this fuel cell technology, with the catalyst (which is Pt based) and MEA (Nafion membrane) being two key contributors towards higher costs.…”