Ionic Liquid–Heteropolyacid: Synthesis, Characterization, and Supercapacitor Study of Films Deposited by Electrophoresis

Hybrid materials based heteropolyacids, silicotungstic acid or phosphomolybdic acid , and a room temperature ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM] ) were synthesized. Carbon analysis showed that of reacts with of and of reacts with of . Fourier transform infrared spectra showed the presence of both 1-butyl-3-methylimidazolium cations and the Keggin anion. Cyclic voltammetry illustrated that the reduction peak potentials of the Keggin anion in the hybrid materials shift toward negative values. The hybrid materials can be suspended in ultrapure water to form true suspensions. Alternating current electrophoretic deposition was used to obtain thick homogeneous films of the hybrid materials in few minutes over stainless steel (SS) wires from aqueous suspensions at and . and previously treated at for were subjected to cyclic voltammetry and galvanostatic charge–discharge cycling in ( 7) and observed to exhibit capacitance behavior between 0 and vs . In ( 7) and in this range of potentials, the hybrid material had an ideal behavior with a stable specific capacitance close to and good cyclability at over .