Increasing the ionic conductivity of sodium-based ceramic-polymer composite electrolytes and improving the interfacial conditions

Studies in the field of solid electrolytes have accelerated due to safety problems such as leakage and ignition of liquid electrolytes. While batteries have become safer with improvements in solid electrolytes, problems like poor contact surface and low strength of solid electrolytes have emerged. These obstacles for the ionic conductivity of electrolytes are being overcome by the development of composite electrolytes; however, the effect of variables such as pressure and temperature on ionic conductivity is not sufficiently understood. This study aims to synthesize NASICON-polymer composite electrolytes and investigate the effects of pressure and temperature on ionic conductivity. For this purpose, an experimental study is conducted covering the production process of electrolytes and the design of a test rig that enables to measure the change of ionic conductivity under pressure and temperature. Solid electrolytes with different proportions of NASICON are prepared. XRD, SEM and FTIR studies are carried out for the characterization of the electrolyte. Electrochemical impedance spectroscopy measurements are taken. The findings indicate that the 25\% NASICON additive electrolyte has the highest ionic conductivity. The ionic conductivity value is measured as 5.19x10^-5 S/cm that is consistent with previous studies. Electrochemical impedance spectroscopy measurements of the samples are taken under various pressure and temperature values, and the mechanisms that explain how these variables affect the ionic conductivity are elaborated.