Towards understanding the poor thermal stability of V~(5+) electrolyte solution in Vanadium Redox Flow Batteries

摘要

The V~(5+) electrolyte solution from Vanadium Redox Flow Batteries was studied by variable temperature ~(17)O and~(51)V Nuclear Magnetic Resonance (NMR) spectroscopy and density functional theory (DFT) based computational modeling. It was found that the V~(5+) species exist as hydrated penta co-ordinated vanadate ion, i.e. [VO_2(H_2O)_3]~(1+). This hydrated structure is not stable at elevated temperature and change into neutral H_3VO_4 molecule via a deprotonation process and subsequently leading to the observed V_2O_5 precipitation in V~(5+) electrolyte solutions.