Toward Standardization of Electrochemical Impedance Spectroscopy Studies of Li-Ion Conductive Ceramics

Ion conductivity of ceramic electrolytes sets a limit to their use in batteries; correct analysis of this parameter opens a gate for further material optimization. Electrochemical impedance spectroscopy (EIS) is the only way to characterize ionic conductivity, but the data obtained could vary from researcher to researcher for a number of reasons. Our goal was to propose a unified approach on the basis of both the published data and our own experience. We synthesized pure Li1.3Al0.3Ti1.7(PO4)3 and analyzed it using EIS, powder X-ray diffraction analysis, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. We show how to (1) obtain reliable EIS spectra; (2) verify the equivalent circuit by adjusting the temperature; and (3) estimate the error of measurement via three approaches highlighting their use for special research aims. Finally, we summarized parameters that should be checked when describing results and benchmarking the results with literature. The article will be useful for those who work with ion-conducting ceramics.