Comparative investigation of electrochemical properties of Li1.5Al0.5Ti1.5(PO4)3 ceramic electrolyte synthesized using different chelating agents for all solid-state batteries

Abstract

NASICON-type oxide solid electrolyte, Li1.5Al0.5Ti1.5(PO4)3 (LATP) is a promising candidate to replace liquid electrolytes due to its low cost, ease of processing, and excellent stability. This study investigates the effect of chelating agents on the properties of LATP solid-state electrolytes (SSEs) synthesized by the sol-gel method. Three different chelating agents are employed: Citric acid, Acetylacetone, and Ethylenediaminetetraacetic acid (EDTA). The thermal, structural, and electrochemical properties of the LATP samples are investigated and evaluated their performance in solid-state batteries. The chelating agents significantly impact the thermal behavior, phase formation, and microstructure of LATP SSEs due to their intrinsic chemical bonding property. LATP using citric acid (c-LATP) exhibits the small grain size of about 2 μm and the highest density of 2.8 g/cm3. The Li//c-LATP//Li cell presents the most stable voltage profile with the lowest overpotential resulting from good ionic conductivity (1.03 × 10−3 S/cm). In addition, The Li//c-LATP//LFP battery shows the highest capacity retention rate (81 %) after 100 cycles and excellent rate performance. These results highlight the importance of chelating agent selection in the sol-gel synthesis of LATP for optimizing its properties and achieving high performance of all-solid-state batteries. © 2024