Abstract
Quaternized polymers are critical components for various energy devices. Vinyl-addition polynorbornenes provide high mechanical strength, high ion conductivity, and chemical stability in a wide range of pH environments due to the all-C-C bond backbone. Herein, we present the synthesis of a series of quaternized polynorbornene random copolymers via vinyl addition polymerization and elucidate the impact of polymer composition on their properties. The quaternary ammonium alkyl tether length and the ratio of n-hexylnorbornene to unsubstituted norbornene are systemically tailored. A copolymer of 5-(3-bromopropyl)-2-norbornene and norbornene with pendant trimethylammonium groups achieved hydroxide conductivity of 109 mS/cm at 80 °C with a modest water uptake of 72%. The addition of n-hexylnorbornene to the copolymer, to make a terpolymer, allows for the polymer composition to be tailored for properties, including a decrease in water uptake and higher processability, despite a slightly decreased hydroxide conductivity. Moreover, the developed membranes are chemically robust and highly mechanically stable, enabling thin membranes to be easily fabricated. This study provides insight into important design parameters for quaternized polynorbornenes for a variety of energy storage and conversion devices, especially fuel cells.
Original language | English |
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Pages (from-to) | 1822-1833 |
Number of pages | 12 |
Journal | ACS Applied Energy Materials |
Volume | 6 |
Issue number | 3 |
DOIs | |
State | Published - Feb 13 2023 |
Funding
This work was sponsored by DOE EERE Hydrogen and Fuel Cell Technologies Office (Program Manager: William Gibbons). We thank Justin Burroughs for performing SEC measurements, Trevor Wilson for demonstrating monomer and catalyst synthesis, and Prof. Brian Long for providing access to his laboratory. We also thank Prof. Chulsung Bae and Dr. Cy Fujimoto for providing SEBS and HTMA-DAPP membranes, respectively, for fuel cell testing. WAXS measurements were enabled by the Major Research Instrumentation program of the National Science Foundation, under Award No. DMR-1827474. A portion of this research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). This work was sponsored by DOE EERE Hydrogen and Fuel Cell Technologies Office (Program Manager: William Gibbons). We thank Justin Burroughs for performing SEC measurements, Trevor Wilson for demonstrating monomer and catalyst synthesis, and Prof. Brian Long for providing access to his laboratory. We also thank Prof. Chulsung Bae and Dr. Cy Fujimoto for providing SEBS and HTMA-DAPP membranes, respectively, for fuel cell testing. WAXS measurements were enabled by the Major Research Instrumentation program of the National Science Foundation, under Award No. DMR-1827474. A portion of this research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ).
Keywords
- anion exchange membrane
- copolymer
- fuel cell
- polynorbornene
- quaternized polymer
- vinyl-addition