Double-Layer Expanded Polytetrafluoroethylene Reinforced Membranes with Cerium Oxide Radical Scavengers for Highly Stable Proton Exchange Membrane Fuel Cells

As a key component of proton exchange membrane fuel cells (PEMFCs), the durability of the proton exchange membranes (PEMs) directly determines the service life of the PEMFCs. As state-of-the-art PEMs, perfluorosulfonic acid (PFSA) membranes suffer from critical mechanical and chemical degradation under actual working conditions. Considering this, we present a strategy to develop highly durable PEMs by intercalating double-layer expanded polytetrafluoroethylene (ePTFE) skeletons and doping CeO2 radical scavengers into the PFSA membranes. The results reveal that the double-layer ePTFE reinforced membranes (DR-Ms) have significantly improved mechanical properties, lower swelling rates, and superior dimensional stability compared to single-layer ePTFE reinforced membranes (SR-Ms). After the wet/dry cycle durability test, DR-Ms show a lower hydrogen crossover increase, reduced power performance attenuation, and smaller membrane impedance increase than SR-Ms. After the open-circuit voltage (OCV) durability test (ODT), DR-Ms exhibit better chemical durability behaviors (such as membrane thinning and OCV decay rates). Furthermore, the 0.5 wt % CeO2-doped DR-M (Ce-DR-M1) imparts a further improved chemical durability during the ODT compared with DR-Ms. In short, the developed Ce-DR-M1 with double-layer ePTFE skeletons and CeO2 radical scavengers is a promising candidate for advanced PEMs with high mechanical and chemical durability for PEMFC applications.

Automated summary

This article presents a strategy to develop highly durable proton exchange membranes (PEMs) for proton exchange membrane fuel cells (PEMFCs) by intercalating double-layer expanded polytetrafluoroethylene (ePTFE) skeletons and doping CeO2 radical scavengers into perfluorosulfonic acid (PFSA) membranes. The results show that the developed membranes have significantly improved mechanical properties, lower swelling rates, and superior dimensional stability compared to conventional single-layer ePTFE reinforced membranes. They also exhibit better chemical durability behaviors and lower hydrogen crossover increase, reduced power performance attenuation, and smaller membrane impedance increase. The CeO2-doped membranes further enhance chemical durability during the open-circuit voltage durability test. Overall, the developed membranes are promising candidates for advanced PEMs with high mechanical and chemical durability for PEMFC applications.