(388d) High Throughput Screening of Ionic Liquids for Enhanced Conductivity

Room temperature ionic liquids (RTILs) are well-known and applied as novel absorbents, solvents, electrolytes, catalysts, and solvents in several fields of scientific research. Since it has a unique structure, RTILs exhibit several significant properties like low vapor pressure, nonflammability, a broad range of liquids, and low melting points. However, neat RTILs have a higher viscosity than organic solvents and low electrical conductivity, which limits the application of neat RTILs in many areas. To overcome these limitations, RTIL is typically mixed with organic solvents to enhance electrical conductivity and reduce viscosity. The screening of RTILs with high electrical conductivity is a significant parameter for its various applications in batteries as an electrolyte, solar and fuel cells, supercapacitors, electrochemical devices, etc. Previous studies report the mixture of RTILs and solvents, which are capable of H-bonding, and the solvents used have a lower viscosity than RTIL. The H-bonding influences the transport behaviour of the ions in the solvent, which defines the electrical conductivity. However, few current research studies emphasized the H-bonding in a mixture of RTILs for the solvent having higher viscosities (like ethylene glycol: EG). Therefore, this study used EG as a solvent to mix RTILs to enhance electrical conductivity. EG has lower vapor pressure and high boiling point than many organic solvents, making it more compatible to apply in different applications. The RTILs were screened by the high throughput method, in which the robotic hand and 96 well plate assisted electrochemical impedance spectroscopy (EIS) method was used to measure the electrical conductivity of the mixtures and neat RTILs. The obtained electrical conductivity was fitted with suitable interpolation methods. The -OH bond interaction was measured with the FTIR analysis and will be a part of this work.