A Dynamically Stable Sulfide Electrolyte Architecture for High‐Performance All‐Solid‐State Lithium Metal Batteries

Abstract All‐solid‐state batteries employing sulfide solid electrolyte and Li metal anode are promising because of their high safety and energy densities. However, the interface between Li metal and sulfides suffers from catastrophic instability which stems the practical use. Here, a dynamically stable sulfide electrolyte architecture to construct the hierarchy of interface stability is reported. By rationally designing the multilayer structures of sulfide electrolytes, the dynamic decomposing‐alloying process from MS 4 (M = Ge or Sn) unit in sulfide interlayer can significantly prohibit Li dendrite penetration is revealed. The abundance of highly electronic insulating decompositions, such as Li 2 S, at the sulfide interlayer interface helps to well constrain the dynamic decomposition process and preserve the long‐term polarization stability is also highlighted. By using Li 6 PS 5 Cl||Li 10 SnP 2 S 12 ||Li 6 PS 5 Cl electrolyte architecture, Li metal anode shows an unprecedented critical current density over 3 mA cm −2 and achieves the steady over‐potential for ≈900 hours. Based upon the merits, the Li||LiNi 0.8 Co 0.1 Mn 0.1 O 2 battery delivers a remarkable 75.3% retention even after 600 cycles at 1 C (1C–0.95 mA cm −2 ) under a low stack pressure of 15 MPa.