Dielectric Constant Measurement for Organic Electrolyte Based on Parallel Plate Capacitor

The dielectric constant is a crucial characteristic of the electrolyte of lithium-ion batteries, which affects the ion mobility and ionic conductivity of the electrolyte. This work proposed an experimental method for measuring the dielectric constant of electrolyte based on the parallel plate capacitance. Several commonly used electrolyte spicies were considered, including ethylene carbonate/dimethyl carbonate (EC/DMC) solvent with a mass ratio of 1:1 and pure acetonitrile (ACN) solvent. The results were in good agreement with theoretical values. In addition, the effect of ion concentration on dielectric constant was investigated. The results show that the dielectric constant of electrolyte decreased with increasing ion concentrations. This could be due to the ion solvation effect which led to a reduction in total dipole moment of the electrolyte. Such characterization of dielectric constant values could contribute in the design of local high concentration electrolyte for next generation batteries.