Effect of doping fillers towards corn starch based green polymer electrolytes / Teoh Kok Hau

Corn starch based polymer electrolytes with lithium perchlorate, (LiClO4), as dopand salt, silica (SiO2) and barium titanate (BaTiO3) as fillers were prepared using solution-casting technique. The prepared corn starch based polymer electrolytes were subjected to scanning electron microscopy (SEM), A.C. impedance spectroscopy, differential scanning calorimetry (DSC), thermal gravimetry analysis (TGA), water solubility test, linear sweep voltammetry (LSV), cyclic voltammetry (CV), galvanostatic charge discharge and low frequency impedance spectroscopy. The addition of fillers alters the ionic conduction mechanism and structural properties of the polymer electrolytes. Ionic conductivity studies were carried out and it was found that the polymer electrolyte systems of corn starch:LiClO4 (60:40), corn starch-LiClO4:SiO2 (96:4) and corn starch-LiClO4:BaTiO3 (90:10) reaches the maximum ionic conductivity of 1.55 × 10-6 S cm-1, 1.23 × 10-4 S cm-1 and 1.84× 10-4 S cm-1, respectively. The addition of filler resulted in better heat resistivity, thermal stability and structural properties. The highest conducting polymer films from each system were used to fabricate electrical double layer capacitor (EDLC) cells. The fabricated cells show wide electrochemical stability windows ~2.7 V. Charge discharge profiles show the EDLCs fabricated have stable performance up to 500 cycles with 90 % efficiency. The highest specific capacitance obtained from the fabricated EDLC cells is 16.22 F g-1. Corn starch polymer electrolytes have shown promising results in EDLC application