Abstract
Selective proton permeation through atomically thin graphene while maintaining impermeability to even small gas atoms i.e. He or hydrated ions, presents potential for advancing proton exchange membranes (PEMs) across a range of energy conversion and storage applications. The incorporation of graphene into state-of-the-art proton conducting polymers e.g. Nafion can enable improvements in PEM selectivity as well as mitigate reactant crossover. The development of facile integration approaches are hence imperative. Here, we systematically study the parameters influencing the integration of monolayer graphene synthesized via scalable chemical vapor deposition (CVD) on polycrystalline Cu foils with a model proton conducting polymer (Nafion) via a facile hot-press process. The hot-press time (t), temperature (T) and pressure (P) are found to not only influence the quality of graphene transfer but can also introduce additional defects in the CVD graphene. Graphene transfers to Nafion performed below the optimum temperature (Topt ∼ 115 °C) remain patchy with ruptures, while transfers above Topt showed defect features, and transfers near Topt show minimal ruptures and defect features. We demonstrate Nafion|graphene|Nafion sandwich membranes using the optimal transfer conditions that allow for ∼50% reduction in hydrogen crossover (∼0.17 mA cm−2) in comparison to Nafion control membranes (∼0.33 mA cm−2) while maintaining comparable proton area specific resistance < 0.25 Ω cm2 (areal conductance ∼ 4-5 S cm−2), that are adequate to enable practical PEM applications such as fuel cells, redox flow batteries, and beyond.
Original language | English |
---|---|
Pages (from-to) | 3473-3481 |
Number of pages | 9 |
Journal | Materials Advances |
Volume | 4 |
Issue number | 16 |
DOIs | |
State | Published - Jul 25 2023 |
Funding
The use of Vanderbilt Institute of Nanoscale Science and Engineering CORE facilities are acknowledged. This work was supported in part by NSF CAREER award #1944134, in part by DOE Early Career Research Program award # DE-SC0022915, in part by the U.S. Department of Energy Isotope Program, managed by the Office of Science for Isotope R&D and Production under award number DE-SC0022237. P. R. K. acknowledges the ECS Toyota Young Investigator Award. Part of this work was performed at the Center for Nanophase Materials Sciences at Oak Ridge National Laboratory, a U.S. Department of Energy Office of Science User Facility. Authors appreciate and acknowledge assistance from Dr. Aaron Daniel at the Department of Chemistry at Vanderbilt University for Differential Scanning Calorimetry measurements.
Funders | Funder number |
---|---|
Office of Science for Isotope R&D and Production | DE-SC0022237 |
National Science Foundation | 1944134 |
U.S. Department of Energy | DE-SC0022915 |
Office of Science | |
Oak Ridge National Laboratory |