Effect of cation size on electrochemical properties of polymer electrolyte


This study investigates the ionic conduction reliance on the size of positively charged ions in electrolytes with double iodide can enhance by incorporating a salt having a bulky cation. Group of gel polymer electrolytes with polyethylene oxide (PEO) as a host matrix based on double salts potassium iodide (KI) and rubidium iodide (RbI) with different weight ratio prepared by using solution cast method. The maximum value of conductivity reaches (6.03×10-3 at 293 K) S/cm for an electrolyte which content (KI 45%, RbI 5%) from binary salt. The ionic conductivity of for gel polymer electrolytes gradually increases by increasing temperature. The real dielectric constant results confirm that the dielectric behavior of the PEO material is a thermally activated process. FTIR results confirm that the shifting of peaks is another way to prove the interactions between PEO and binary salt ascribed to the creation of a passing cross-linking complex between the ether oxygen of the PEO and the positively charged ions of the ionic liquids.