Polymer/ceramic interfacial layer enables stable cycling of all-solid-state Li-metal batteries with sulfide electrolyte

The interfacial stability, particularly between lithium metal and the solid electrolyte, as a critical challenge in solid-state batteries leads to rapid lithium-dendrite growth and increased internal resistance. In this study, we tackled these issues by developing a stable interface between sulfide electrolytes Li5.5PS4.5Cl1.5 (LPSCl) and the metallic lithium anode, using a polyethylene oxide (PEO) layer integrated with Li-ion conducting oxide electrolyte Li1.3Al0.3Ti1.7(PO4)3 (LATP). The uniform distribution of LATP within the PEO matrix through a simple stirring process enhanced the mechanical strength of the PEO interlayer and minimizes both the interfacial reactions and lithium dendrite formation. A Li/Li symmetric cell incorporating this LATP-integrated layer exhibited a low interfacial resistance, ensuring stable cycling for 2800 h at a current density of 0.2 mA cm−2 at 60 °C.