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

Abstract

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 CeO 2 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 % CeO 2 -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 CeO 2 radical scavengers is a promising candidate for advanced PEMs with high mechanical and chemical durability for PEMFC applications.

Preparation of an Integrated Membrane Electrode Assembly for Proton Exchange Membrane Fuel Cells Using a Novel Wet-Bonding Strategy

“…It is noteworthy that the ionomer fills into the micropores of ePTFE reinforcement and no pore is observed in ePTFE/ionomer combination region . The electrolyte dispersion with preferred flowability can easily fill the micropores (78% porosity) of ePTFE reinforcement and reach the upper surface ePTFE reinforcement through the micropores. ,, This means that the ePTFE microporous reinforcement should not significantly affect the proton conductivity of PEM …”

“…38 The electrolyte dispersion with preferred flowability can easily fill the micropores (78% porosity) of ePTFE reinforcement and reach the upper surface ePTFE reinforcement through the micropores. 26,40,41 This means that the ePTFE microporous reinforcement should not significantly affect the proton conductivity of PEM. 41 As shown in Figure 2g, the thickness of the commercial GORE-SELECT PEM in MEA-CCM is ∼13−15 μm, and the middle is an ePTFE/Nafion combination region with a thickness of ∼4 μm.…”

“…26,40,41 This means that the ePTFE microporous reinforcement should not significantly affect the proton conductivity of PEM. 41 As shown in Figure 2g, the thickness of the commercial GORE-SELECT PEM in MEA-CCM is ∼13−15 μm, and the middle is an ePTFE/Nafion combination region with a thickness of ∼4 μm. For the MEA-NRs and MEA-DMD, the thickness of the PEM prepared by direct membrane coating is ∼13−15 μm, and the ePTFE/Nafion combination region is ∼3−4 μm, as observed in Figures 2h and 2i.…”

Improvement of Selectivity of RALEX-CM Membranes via Modification by Ceria with a Functionalized Surface

“…One of the promising dopants is ceria. Ceria-doped membranes are highly stable during fuel cell operation [ 32 , 33 ], effective in water purification by reverse osmosis [ 34 ] and nanofiltration, and even have antibacterial properties [ 35 ], which can favorably affect the stability and service life of membranes. The reason for the unique antioxidant and antibacterial properties of ceria is its ability to interact with highly reactive oxygen radicals (hydroxyl radicals, superoxide radicals, etc.)…”

Improved performance of nafion membranes by blending ultra-high molecular weight polyvinylidene fluoride

“…As the climate warming gradually become a global consensus, the nations of the world are vigorously developing clean energy technologies to reduce carbon emissions produced by the fossil energy. Proton exchange membrane fuel cells (PEMFCs) have become one of the promoting power generation systems in the 21st century due to its high density of energy, simple design, low operation temperature and zerocarbon emissions [1][2][3][4][5][6]. As a critical component in PEMFCs system, proton exchange membrane (PEM) works as H+ conductor and separator between oxygen and fuel [7,8].…”