Structure and ionic conductivity of NASICON-type LATP solid electrolyte synthesized by the solid-state method

Abstract

The area of commercial battery innovation to replace safer batteries in widely used secondary batteries offers promising research into solid-state electrolytes (SSEs). Compared to lithium-ion electrolytes, solid-state electrolytes are inherently safer because they replace solvents with non-flammable materials. One of the promising materials for electrolytes today is based on inorganic materials, especially ceramics. Ceramics with superior mechanical, chemical and electrochemical stability and stability against high temperatures are of great interest. NASICON structured Li1.3 Al0.3 Ti1.7 (PO4)3 (LATP) is the most studied type of solid electrolyte due to its stability against air and humidity and high ionic conductivity.In this study, LATP samples were synthesized by solid-state synthesis method. The structural, morphological and charge transport properties (ionic conductivities) of the synthesized samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Since the modifications applied during the sample preparation process can change the crystal structure and size of the target material, in this study, in order to minimize the formation of impurity phases and to achieve high ionic conductivity it was applied the different synthesis steps (temperature, time, grinding speed, etc.) from the literature. While the ionic conductivity value obtained is among the best values obtained by LATP synthesis methods in the literature, it is the best ionic conductivity value (1.3 × 10−3 S cm−1) obtained by the solid state synthesis method.