Lithium Migration Mechanism in Lithium Zirconium Oxide Coating Layers for All-Solid-state Lithium Batteries

Solid-state batteries utilizing sulfide-based solid electrolytes encounter challenges stemming from inadequate oxidation-reduction stability and undesired side reactions at the electrode/electrolyte interfaces. To address these issues, studies have employed electrode surface coating techniques. This study investigates the lithium migration mechanism within different lithium zirconium oxide compositions via crystallographic analysis. This investigation highlights the considerable potential of Li6Zr2O7 among these compositions. Within the Li6Zr2O7 structure, the analysis reveals distinct lithium diffusion barriers spanning from approximately 0.35 eV to 0.45 eV and 0.878 eV, indicating diverse pathways for lithium ion diffusion. Notably, the Li6Zr2O7-coated cathode exhibits remarkedly improved cyclability in an all-solid-state battery system. These findings underscore the importance and viability of exploring diverse structures and compositions of coating materials, moving beyond conventional options, such as LiNbO3 and Li4Ti5O12.