Enhanced structural, electrical, and electrochemical performance of polyethylene oxides (PEO)-based polymer electrolytes for solid state K⁺ ion batteries

Flexible polymer electrolytes with effective electrochemical characteristics must be developed to meet smart electronic technology demands. The current investigation explores the solid polymer electrolytes (SPEs) prepared by solution-casting technique, using polyethylene oxides (PEO) doped with KCl salt in different weight percentages. The effect of the dopant on the chemical interactions and structural, optical, thermal, electrical, and electrochemical properties were studied using various strategies. It was found that the incorporation of KCl salt to PEO results in a three order of magnitude enhancement in ionic conductivity of polymer matrix from 10-9 to 10(-6) S cm(-1). The PEO doped with 20 wt.% KCl salt exhibited the highest ionic conductivity (4.32 x 10(-6) S cm(-1)) and low activation energy (0.25 eV). According to the thermal analysis, the thermal stability of the films improved as the dopant concentration increased. Further, the electrochemical strength improved with increasing dopant concentration, according to cyclic voltammogram experiments. From the results of all the characterizations, PEO loaded with 20 wt.% KCl SPE system is a suitable candidate for use as an electrolyte in energy storage devices such as solid-state batteries.