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 × 10 −8 S cm −1 (Li 8 La 2 Zr 2 O 11 ) to 1.18 × 10 −6 S cm −1 (Li 18 La 2 Zr 2 O 16 ), 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 LiCoO 2 (LCO) and LiNi 0.8 Mn 0.1 Co 0.1 O 2 (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.