Deep insight of interfacial stability of LiNi0.7Co0.1Mn0.2O2-based all-solid-state battery with superior performances

Chlorine-rich argyrodite Li5.5PS4.5Cl1.5 with low-cost and high ionic conductivity displays great potential as a solid electrolyte for solid-state battery. However, poor compatibility with bare high-voltage cathode limits its applications. Here, the Li2ZrO3 coating and Li3InCl6 isolating layer strategy are employed to mitigate the interfacial instability between Li5.5PS4.5Cl1.5 electrolytes and LiNi0.7Co0.1Mn0.2O2 materials, respectively. A diversified combination of two strategies is applied to construct all-solid-state batteries with a long lifespan and high energy density. Electrochemical performance results indicate that introducing Li3InCl6 electrolyte in the cathode mixture yields high discharge capacities at beginning and then suffers rapid capacity degradation during extended cycling. In contrast, the assembled Li2ZrO3@LiNi0.7Co0.1Mn0.2O2/Li5.5PS4.5Cl1.5/Li–In battery delivers slightly lower capacities and superior capacity retention. Multiple characterization methods are employed to unravel the mechanism behind battery performance differences. The poor cycle performance of Li3InCl6-involved solid-state battery configurations is partially associated with the decomposition of Li3InCl6 in the cathode mixture. The Li2ZrO3 coating layer mitigates the side reaction between LiNi0.7Co0.1Mn0.2O2 and Li3InCl6, resulting in enhanced capacities and improved cyclability. Furthermore, the interfacial instability between Li3InCl6 and Li5.5PS4.5Cl1.5 electrolytes leads to the poor cycling performance of batteries containing the Li3InCl6/Li5.5PS4.5Cl1.5 bilayer structure. This work offers a comprehensive guide for designing high-performances all-solid-state lithium batteries.