In Situ Polymerization-Enabled Facile Electrode Interface in Solid-State Lithium–Metal Batteries

Here, a ceramic–polymer composite membrane consisting of P(VDF-HFP), LiTFSI, and a high-entropy rhombohedral NASICON-structured ceramic filler Li 1.3 Al 0.1 Sc 0.1 Y 0.1 Sn 1.7/3 Zr 1.7/3 Ti 1.7/3 (PO 4 ) 3 was employed as the solid electrolyte in the batteries. Further, the facile electrode interface was engineered via ring polymerization of 1,3-dioxolane (DOL) containing different lithium salts (LiTFSI, LiFSI, and LiDFOB) catalyzed by a LiPF 6 salt. The synergistic effect of different salts provided a robust interphase at the lithium metal interface, enabling stable lithium plating/stripping in Li|Li coin cell configurations with a critical current density of ∼1 mA cm –2 at room temperature. The in situ polymerized matrix also facilitated the formation of potential lithium-ion conduit channels at the cathode side and the electrolyte–electrode interface, thereby mitigating key transport limitations that hinder the performance of conventional polymer electrolyte-based solid-state batteries. The Li|LiFePO 4 coin cell configuration demonstrated excellent cyclability with a discharge capacity of 107 mAh g –1 after 500 cycles at 1C.