Room-temperature ionic liquids (RTILs) have gained significant attention across various scientific disciplines due to their versatility as absorbents, solvents, electrolytes, and catalysts. Their distinct molecular structure imparts several advantageous properties, such as negligible vapor pressure, inherent nonflammability, a wide liquid-phase temperature range, and relatively low melting points. Despite these benefits, pure RTILs often suffer from high viscosity and limited electrical conductivity, which restrict their direct use in several electrochemical applications. RTILs are frequently blended with organic solvents to address these challenges of reducing viscosity and improving ionic conductivity. Identifying RTIL systems with superior conductivity is vital for their integration into batteries, supercapacitors, solar and fuel cells, and other electrochemical technologies. Prior research has primarily focused on RTIL–solvent mixtures involving low-viscosity solvents capable of hydrogen bonding, as such interactions significantly influence ionic transport and, consequently, electrical conductivity. However, limited work has explored the role of hydrogen bonding in RTIL mixtures with higher-viscosity solvents such as ethylene glycol (EG). In this study, EG was employed as a co-solvent to enhance the conductivity of RTIL mixtures. Its high boiling point and low vapor pressure make it a suitable candidate for various practical applications. A fully automated high-throughput screening system was developed using a robotic arm and 96-well microtiter plates, enabling rapid ionic conductivity measurement through electrochemical impedance spectroscopy (EIS). A theoretical model was developed to explain the improved conductivity of RTIL–EG mixtures, considering ion dissociation, viscosity, and molal volume. The optimized mixture, applied in a CO₂ capture process, reduced energy consumption by nearly 50%. This highlights the effectiveness of the high-throughput screening platform and its potential for optimizing RTIL–solvent systems across various applications.
