Ionic Conductivity, Dielectric, and Structural Insights of Deep Eutectic Solvent-based Polymer Electrolyte: A Review

The exponential concern about environmental concerns has heavily driven the development of green technology. In light of these needs, Deep Eutectic Solvent (DES) emerged as a green solvent and additive, characterized by its minimal toxicity, volatility, biodegradability, and biocompatibility, as well as the simplicity of synthesis, high yields, purity, and the availability of its precursors. This review is intended to summarise and discuss polymer electrolytes based on DES for better insight into the potential of replacing conventional organic solvents or ionic liquids for energy storage applications in the aspect of their electrical and structural properties. Therefore, an examination of dielectric studies is conducted as they hold significance in establishing a correlation between the rise in ionic conductivity and the augmentation of freely movable ions, thereby highlighting the importance of investigating the dielectric properties of an electrolyte. Besides, XRD and morphological studies in this work can show how ionic conductivities can influence the size of pores in DES-based polymer electrolytes.