Atomic layer deposition of ZnO on Li1.3Al0.3Ti1.7(PO4)3 enables its application in all solid-state lithium batteries

Abstract

BackgroundAll-solid-state Li batteries (ASSLBs) are emerging as potential electrochemical energy storage devices for next-generation large-scale electrical power systems. In particular, Li1.3Al0.3Ti1.7(PO4)3 (LATP) is an efficient cost-effective solid-state electrolyte with high ionic conductivity for high energy density and safety ASSLBs. Since LATP is unstable verus metallic Li. Therefore, the application of Li-based all-solid-state batteries is practically limited. MethodsAs a possible solution to overcome the LATP instability, the interface was modified by adding a 5 nm thin ZnO layer on LATP using the atomic layer deposition (ALD) technique. Significant FindingsThe ZnO layer reduces the observed overpotential in a Li|ZnO@LATP|Li symmetric cell compared to an unmodified LATP-based cell. In contrast to the unmodified LATP-based Li cells, the ZnO-modified symmetric LATP-based Li cells show stable cycling for more than 500 h without a short circuit. The full-cell configuration of the LiFePO4|ZnO@LATP|Li system showed a reversible capacity of 156 mAh/g over 50 cycles and exposed good capacity retention (98.79% after 50 cycles) during the cycling test. The results indicate that ZnO coating by ALD on LATP could overcome the stability issues of pristine LATP versus metallic Li. Therefore, this work will lead to prove the simple manner of interfacial modification and improvement of electrochemical performance of inorganic oxide based solid electrolytes for all-solid-state lithium battery applications.