Effect of different cation on PVA/IL solid electrolyte for electrochemical supercapacitor

Abstract

Poly (room temperature ionic liquids-RTIL) with the different cationic centre have been explored for high operating voltage supercapacitor application. Ionic liquids with different cations (phosphonium, ammonium, and sulfonium) based transparent gel electrolytes were formulated by adopting polyvinyl alcohol (PVA) which could assemble supercapacitor device. To establish the impact of changing the cationic centre in conduction mechanism and molecular dynamics broadband dielectric spectroscopy was used. The dielectric results show the ion dynamics in the whole frequency range has a dependency on the cationic centre. The supercapacitor fabricated with the resultant PVA/ILs and activated carbon electrode were tested with cyclic voltammetry, galvanostatic charge–discharge curves, and impedance spectroscopy. The electrochemical results return a step towards to the chemical and physical properties of an IL can be made the system by changing their cations in a suitable operation. Among the preferred samples, the highest conductivity (1.5 × 10−3 S/cm), specific capacitance (400 F/g) and energy density (56.25 Wh/Kg) were obtained for sulfonium cationic core RTIL polymer electrolyte.