Studies on the plasticization efficiency of deep eutectic solvent in suppressing the crystallinity of corn starch based polymer electrolytes

A series of polymer electrolytes composed of corn starch (CS), lithium bis(trifluoromethanesulfonyl)imide (LITFSI) and deep eutectic solvent (DES) were fabricated by solution casting technique. The DES was synthesized from a mixture of choline chloride and urea at a molar ratio of 1:2. The addition of DES is crucial in enhancing the room temperature ionic conductivity by increasing the amorphous elastomeric phase in CS:LITFSI matrix. The ionic transport mechanism is improved and appreciable amount of ion conducting polymer electrolytes is produced. The highest ionic conductivity achieved for the polymer electrolyte composition CS:LiTFSI:DES (14 wt.%:6 wt.%:80 wt.%) is 1.04 × 10−3 S cm−1. The anomalies that were observed with the addition of DES upon formation of neutral ion multiples were visually revealed by the SEM micrographs. The possible dipole–dipole interaction between the constituents was visualized by the FTIR spectroscopy upon change in cage peaks.