A Study of Electrochemical Impedance Spectroscopy of β-alumina Na2O·11Al2O3 and NASICON Type Li1.3Al0.3Ti1.7(PO4)3

Abstract

Solid electrolytes are functional materials with high ionic conductivity. The conductivity highly depends on the microstructure such as grains and grain boundaries. For most solid electrolytes, both grain and grain boundary contribute to the conductivity. In order to better understand the conductive mechanism, it is important to identify the contribution of grain and grain boundary. Electrochemical impedance spectroscopy (EIS) was used to measure the impedance of β-alumina Na2O·11Al2O3 and NASICON type Li1.3Al0.3Ti1.7(PO4)3 (LATP) by the impedance complex plan. Activation energy is an important factor to identify materials. The bulk property and grain boundary property were distinguished according to the activation energy of each property. An equivalent circuit which contains external influence factor components was built to simulate the electrical properties to make the electrical properties of each electrolyte much accurate. The fitting results show high coincidence with the origin plots obtained by the EIS test. The physical significance of the equivalent circuit is explained theoretically and experimentally.