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For achieving economically viable polymer electrolyte membrane fuel cells (PEMFCs) in the commercial market, simplifying the fabrication process and manufacturing of robust membrane electrode assembly (MEA) are important. Herein, a single spray‐coating method for developing a robust and free‐standing reinforced Nafion composite membrane and electrodes is reported. By comparing the fabricated membrane's morphology under diverse process conditions including the nozzle‐to‐substrate distance and solution‐loading rates, the optimized spray‐coating for uniformly deposited spray‐based membrane without any defects has been determined. To explain this optimized condition, a simple theoretical model based on the concept of the surface coverage of sprayed droplets is proposed. The fabricated multiwalled carbon nanotubes/CeO2‐reinforced Nafion composite membrane shows excellent mechanical properties with minimal proton‐conducting loss despite using additional fillers of total 4 wt% in the Nafion matrix. By successively depositing the catalyst layer on that membrane using the same spray‐coating device, an MEA with the reinforced spray‐based membrane has been successfully fabricated; moreover, diverse electrochemical measurements and durability tests have been conducted. The MEA with the reinforced membrane shows comparable initial performance and considerably higher performance after the durability test compared to the MEA with commercial Nafion membrane. [ABSTRACT FROM AUTHOR]

Summary: Improving the durability of the membrane electrode assembly (MEA) while obtaining high performance is required to further commercialize polymer electrolyte membrane fuel cells (PEMFCs). The durability of PEMFCs is improved by incorporating radical scavengers, such as CeO2 (ceria), into the MEA, especially the membrane. However, nanosized ceria particles are generally mixed with ionomers and are cast on substrates to fabricate composite membranes. In such a case, controlling their morphology and avoiding particle agglomeration is difficult. Herein, we report a novel method for constructing a robust membrane by incorporating ultrathin ceria barriers into the outermost sides of a commercial Nafion membrane to effectively alleviate radical attacks while ensuring the high uniformity and controllability of ceria layers. The improved durability of the composite membrane is confirmed via ex situ Fenton's test and in situ operation of a fuel cell. Moreover, we observe that the amount of fluoride ion emission and the loss of proton conductivity of the membranes decrease as the CeO2 density increases. The MEA comprises a modified membrane with CeO2 barriers that show proper areal density. It demonstrates excellent durability under accelerated environmental conditions (open circuit voltage test) and acceptable initial performance with an insignificant decrease in proton conductivity. [ABSTRACT FROM AUTHOR]