Blending polybenzimidazole with an anion exchange polymer increases the efficiency of vanadium redox flow batteries
| Autor: | Dirk Henkensmeier, Yongchai Kwon, Mina Jung, Anastasiia Konovalova, Wonmi Lee, Gyu Seong Yi, Sangwon Kim, Chanho Noh |
|---|---|
| Rok vydání: | 2019 |
| Předmět: |
chemistry.chemical_classification
Materials science Ion exchange Vanadium chemistry.chemical_element Filtration and Separation Sulfuric acid 02 engineering and technology Polymer Conductivity 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Biochemistry 0104 chemical sciences chemistry.chemical_compound Membrane chemistry Chemical engineering Nafion Ultimate tensile strength General Materials Science Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | Journal of Membrane Science. 580:110-116 |
| ISSN: | 0376-7388 |
| DOI: | 10.1016/j.memsci.2019.03.014 |
| Popis: | PBI membranes are recently discussed as stable, well performing membranes for vanadium redox flow batteries (VRFB). Blending meta-PBI with an anion exchange polymer (FAA3i) slightly reduces the coulomb efficiency from 99.7 to 97.8%, but strongly increases the voltage efficiency from 82.5 to 88.2%, leading to an increased energy efficiency (86.2% at 80 mA cm−2), exceeding that of meta-PBI (82.2%) and N212 (83%). Apparently, since the conductivity of sulfuric acid has a maximum around a concentration of 3.8 M, the concentration of the absorbed acid has a dominant influence on the conductivity. Addition of FAA3i decreases the concentration of the acid absorbed by PBI membranes. Furthermore, an ex-situ stability test in 1.5 M V5+ solutions in 2 M sulfuric acid for 87 days showed a very high stability for meta-PBI and Nafion 212, while the commercial FAA3 membrane disintegrated into pieces. Blending of meta-PBI and FAA3 decreased the stability, as proven by formation of V4+, but all tested blend membranes retained their membrane shape and could still be handled. Blending with FAA3 reduces the tensile strength and Young's modulus of meta-PBI, and doping with sulfuric acid leads to a further decrease in the mechanical strength. However, an acid doped PF-21 still showed a tensile strength of 37 MPa and a Young's modulus of 0.7 GPa. |
| Databáze: | OpenAIRE |
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