Solution Processing of Lithium-Rich Amorphous Li-La-Zr-O Ion Conductor and Its Application for Cycling Durability Improvement of LiCoO2 Cathode as Coating Layer

Abstract

Lithium-rich amorphous Li-La-Zr-O (a-Li-La-Zr-O) electrolyte is successfully synthesized using sol-gel processing method. With unlimited compositions of the amorphous structure, lithium-rich compositions are systematically investigated to determine optimal composition and optimized processing conditions of a-Li-La-Zr-O coatings. There is an improvement in ionic conductivity of a-Li-La-Zr-O with Li content increasing, specifically from 3.0 x 10(-8) S cm(-1) (Li8La2Zr2O11) to 1.18 x 10(-6) S cm(-1) (Li18La2Zr2O16), thereby resulting in low activation energy. The high-ionic-conductivity a-Li-La-Zr-O is implemented as an artificial solid electrolyte interface coating layer on cathode materials. The a-Li-La-Zr-O-coated LiCoO2 (LCO) and LiNi0.8Mn0.1Co0.1O2 (NMC 811) coin cells exhibit better cycling performance than the bare coin cell at the optimum compositional ratio of a-Li-La-Zr-O. A-Li-La-Zr-O can be a promising material for solid electrolyte battery and a potential coating layer for the modification of cathode surface.