Nuclear Magnetic Resonance Studies on Vanadium(IV) Electrolyte Solutions for Vanadium Redox Flow Battery
The vanadium (IV) electrolyte solutions with various vanadium concentrations are studied by variable temperature 1H and 17O Nuclear Magnetic Resonance (NMR) spectroscopy. The structure and kinetics of vanadium (IV) species in the electrolyte solutions are explored with respect to vanadium concentration and temperature. It was found that the vanadium (IV) species exist as hydrated vanadyl ion, i.e. [VO(H2O)5]2+ forming an octahedral coordination with vanadyl oxygen in the axial position and the remaining positions occupied by water molecules. This hydrated vanadyl ion structure is stable in vanadium concentrations up to 3M and in the temperature range of 240 to 340 K. The sulfate anions in the electrolyte solutions are found to be weekly bound to this hydrated vanadyl ion and occupies its second coordination sphere. The possible effects of these sulfate anions in proton and water exchange between vanadyl ion and solvent molecules are discussed based on 1H and 17O NMR results.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 989029
- Report Number(s):
- PNNL-SA-71574; 44591; 30406
- Journal Information:
- Journal of Power Sources, 195(22 SP ISS):7709-7717, Journal Name: Journal of Power Sources, 195(22 SP ISS):7709-7717 Journal Issue: 22 Vol. 195; ISSN 0378-7753
- Country of Publication:
- United States
- Language:
- English
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