Fig. 5: Schematic illustration of microstructural changes in ASSBs induced by chemical degradation.

The LiDFP coating layer effectively mitigates chemical degradation at the cathode–SE interfaces, thereby encouraging more homogeneous cathode behavior. This results in smaller and more homogeneous pore formation while maintaining contact integrity between the cathode and coating layer, suggesting a potential pathway for lithium diffusion from the solid electrolyte to the cathode through the coating layer.