Bridging Large-Scale Manufacturability and Nanoscale Interfacial Chemistry in Lithium Metal Solid-State Batteries

To address interfacial instability in Li metal all-solid-state batteries, protective interlayers have been adopted, yet most rely on coatings or noble metal additives incompatible with scalable manufacturing. Here, we report a nanosized red phosphorus-based interfacial design that enables autogenous chemo-wetting upon contact with Li, spontaneously forming a Li₃P-rich interphase, referred to as the autogenous chemo-wet interlayer. This reactive layer self-regulates ionic transport and interfacial adhesion through in situ chemical conversion, producing uniform Li-ion flux and well-distributed interfacial current, thereby enabling stable plating and stripping at high current densities and reliable high-rate solid-state cycling. The chemo-wetting mechanism is inherently compatible with roll-to-roll transfer printing and enables defect-free lamination across large-area electrodes. This coupled mechanical-electrochemical regulation underpins scalable fabrication of solid-state electrodes, as demonstrated in 6 Ah-class pouch cells. These discoveries bridge nanoscale interfacial reactivity with macroscale processability and present a step toward practical implementation toward high-energy, large-format solid-state Li metal batteries.