Organotrifluoroborate salts

2017-02-27T23:18:32Z (GMT) by Maganti, Radha
New types of organotrifluoroborate (RBF3-) salts are described in this thesis, primarily made and studied for the purpose of applying them as electrolytes in electrochemical devices. Electrolytes are an important potential application of ionic liquids (ILs) since their properties are extremely attractive in this role. Their main disadvantage in this application is their typically high viscosity, which limits mass transport rates in the electrolyte media. However, the overall performance of an electrolyte is not solely dependant on the viscosity of the IL. Taking dye-sensitized solar cells (DSSCs) as a currently investigated IL application, overall efficiencies appear to also be dependent on the type of IL. Therefore, the new RBF3- salts were synthesized with the aim of producing salts that could potentially exhibit low viscosity liquids or good conductive solids. The salts were also characterised for their electrolyte properties and those with good potential were further studied with the redox couple triiodide/iodide for use in DSSCs. Tribology studies were carried out for a phosphonium-based RBF3- that showed relatively good potential as a lubricant. The salt also showed improved wear and maintained friction with an increased severity of test condition. The RBF3- ions were also tested for their hydrolytic stability, following a study that revealed the hydrolytic instability of the tetrafluoroborate ion (BF4-). The study involved the use of pH measurement as a primary detection of the anion decomposition in water, from which the by-product is hydrofluoric acid. The result is that the RBF3- ions proved to be more hydrolytically stable to BF4-.