Scalable Dual‐Interface Engineering for High Ionic Conductive, Mechanical Robust Sulfide Membranes in High‐Energy All‐Solid‐State Li‐Metal Batteries

All‐solid‐state Li‐metal batteries (ASSLMBs) integrating sulfide electrolyte membranes with Li‐metal anodes and Ni‐rich layered cathodes represent a pragmatic strategy for realizing the elusive 400 Wh kg −1 . Nevertheless, their implementation is plagued by exacerbated electrode/electrolyte interfacial incompatibilities and mechanical failures that degrade energy output and cycling stability. Herein, a versatile dual‐interface engineering paradigm is proposed that combines Li 5.3 PS 4.3 ClBr 0.7 (LPSCB) electrolyte with great Li‐metal compatibility and Li 1.75 ZrCl 4.35 O 0.5 F 0.4 (LZCOF) electrolyte with superior cathode compatibility. The robust 40‐µm‐thick LPSCB membrane achieves ultrahigh ionic conductivity (3.05 mS cm −1 ) and dendrite suppression capability (critical current density reaching 1.5 mA cm −2 ). Meanwhile, micron‐sized LZCOF particles are uniformly coated on LiNi 0.88 Co 0.06 Mn 0.06 O 2 (NCM88) cathode through facile ball‐milling, substantially mitigating interfacial degradation. Therefore, well‐configured LZCOF@NCM88/LPSCB membrane/Li cells demonstrate exceptional fast‐charging capability (136.1 mAh g −1 at 1.0 °C), and capacity retention (88.9% retention after 1000 cycles at 0.5 °C). Furthermore, the ASSLMB at 30 °C attains a remarkable cell‐level energy density of 414.3 Wh kg −1 at a high loading of 4.62 mAh cm −2 and maintains stability for 400 cycles. This work represents a scalable dual‐interface engineering strategy enabling sulfide membranes for high‐energy ASSLMBs.