Electrospun Nanofiber Electrodes for Boosted Performance and Durability at Lower Humidity Operation of PEM Fuel Cells

Abstract

The need for the development of new materials and strategies to enhance the performance of the PEM fuel cell at low humidity and platinum (Pt) loadings is becoming increasingly crucial. Due to this fact, the current study presents the fabrication of electrospun sulfonated silica (S-SiO2) as a poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE))-based, flexible, freestanding, and highly porous novel cathode structure for PEM fuel cells. The developed fiber-based P(VDF-TrFE)/Pt/C/S-SiO2cathodes are compared with electrospun PVDF/Pt/C/S-SiO2, PVDF/Pt/C/Nafion, and conventionally sprayed electrodes to evaluate the utility of a new (carrier) P(VDF-TrFE) polymer in electrode structure. Morphological analyses revealed that S-SiO2and Pt/C particles were homogeneously distributed along the fibers without any significant agglomerations. The MEAs prepared by fiber-based P(VDF-TrFE)-Pt/C/S-SiO2cathodes with low Pt loadings (0.1-0.15 mg cmPt-2) demonstrated promising fuel cell performance recording up to 417.7 mW cm-2. It also exhibited a remarkable power output retention (98.2%) under partially humidified conditions. In situ electrochemical measurements reveal that enhanced particle distribution and Pt/S-SiO2surface contact results in the cathode performance surpassing that of conventional sprayed and fiber-based PVDF/Pt/C/Nafion cathodes. The fiber-based P(VDF-TrFE)/Pt/C/S-SiO2cathodes exhibited a promising durability record retaining up to 86.5% of their maximum power output after 30 000 cycles of a Pt-dissolution accelerated stress test (AST). Furthermore, P(VDF-TrFE)-Pt/C/S-SiO2cathodes with high S-SiO2loadings exhibited a 2.7% gain in maximum power density after 1000 cycles of a carbon corrosion durability test.