The effect of ionic liquid on the development of poly(vinyl alcohol) (PVA)-based ion conductors for electric double layer capacitors application

Poly(vinyl alcohol) (PVA)-lithium trifluoromethanesulfonate (also known as lithium triflate) (LiTf) polymer electrolytes incorporated with different weight ratios of ionic liquid, 1-butyl-3-methylimidazolium bromide (BmImBr), were prepared by solution casting method. Upon the addition of 50 wt% BmImBr, the ionic conductivity increases from (9.73 +/- 0.04) x 10(-6) S cm(-1) to (1.96 +/- 0.01) x 10(-4) S cm(-1) at room temperature. Besides, the ionic liquid free-polymer electrolyte obeys the Arrhenius theory which is related to thermally-activated principle. The glass transition temperature (T-g) of polymer electrolytes also demonstrate a decreasing trend in Differential Scanning Calorimetry (DSC) thermogram. This decrease in T-g is mainly due to the plasticising effect of BmImBr. The Fourier-Transform Infrared (FTIR) studies indicate complexation between the PVA, LiTf and BmImBr. The fabricated EDLC demonstrate its specific capacitance of 19.5 Fg(-1), energy density of 1.4 W h kg(-1) and power density of 15 kW kg(-1).

Automated summary

The addition of ionic liquid BmImBr significantly improves the ionic conductivity of PVA-LiTf polymer electrolytes, exhibiting compliance with the Arrhenius theory and a decrease in glass transition temperature. Fourier-Transform Infrared studies reveal complexation between PVA, LiTf, and BmImBr.