Surfactant-Free Microemulsion Electrolyte with Topological Solvation and Thermal Resilience for Zinc-Ion Batteries.

Aqueous Zinc-Ion Batteries (AZIBs) are a potential alternate to conventional batteries; however, their commercialization is dampened by the existing underlying problems in their operation. This work combines a molecular level understanding using molecular dynamics simulations of a potential greener electrolyte formed using surfactant-free microemulsion systems and comparing their responses when subjected to temperatures ranging from 273 to 343 K. Two different systems n-butanol-ethanol-water (BEW) and triethyl citrate-pentanediol-water (PTW) were first mixed with organic zinc acetate salt and then were subjected to a temperature gradient. The insights after analyses reveal that the systems comprise preferential solvation and the ions are encapsulated by the organic compound layer. Thermodynamic analyses comprising of interaction energy and solvation free energy reveal that the systems maintain a balance between the enthalpic loss by compensating it with entropic gain. The PTW system surpasses BEW in structural stability and thermal resilience.