Studies on ionic liquid-based corn starch biopolymer electrolytes coupling with high ionic transport number

Biopolymer electrolytes containing corn starch, lithium hexafluorophosphate (LiPF₆) and ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BmImTf) were prepared by solution casting technique. The ionic conductivity was found to increase with increasing ionic liquid concentration. Upon doping with 80 wt% of BmImTf, the ionic conductivity increased by three orders of magnitude. The highest ionic conductivity of (3.21 ± 0.01) × 10^?4 S cm^?1 was achieved at ambient temperature. The complexation between corn starch, LiPF₆ and BmImTf was further proven in attenuated total reflectance-Fourier transform infrared findings. The highest conducting biopolymer electrolyte was stable up to 230 °C, as proven in thermogravimetric analysis.