M. Vijayakumar, S. Burton, Cheng Huang
Nov 15, 2010
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Influential Citations
81
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Quality indicators
Journal
Journal of Power Sources
Abstract
Abstract The vanadium(IV) electrolyte solutions with various vanadium concentrations are studied by variable temperature 1 H and 17 O 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(H 2 O) 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 3 M and in the temperature range of 240–340 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 1 H and 17 O NMR results.