Pressure‐Related Challenges and Strategic Approaches in Lithium Metal Sulfide all‐Solid‐State Batteries

Sulfide solid electrolytes, owing to their high ionic conductivity and excellent plasticity, are considered among the most promising candidates for lithium metal all-solid-state batteries. Nevertheless, practical cell assembly and cycling typically rely on externally applied pressure to secure intimate electrode-electrolyte contact and continuous ion-transport pathways. Pressure governs not only densification and interfacial wetting of the sulfide phase but also the distribution of mechanical stress, local current density, and Li-deposition morphology. While high pressure can suppress interfacial resistance and pore formation, it may simultaneously induce electrolyte fracture, particle pulverization, and accelerated dendrite penetration, posing a critical obstacle to practical implementation. This review analyzes the influence of pressure on structural evolution of sulfide electrolytes, interfacial chemistry, ion-transport behavior, and Li-plating kinetics. Recent advances in mitigating pressure dependence-through interface modification, electrode structural engineering, and flexible or quasi-isostatic loading designs-are systematically summarized. Finally, we highlight that constructing interfaces capable of stable operation under low or even zero applied pressure is essential for the technological transition of sulfide-based solid-state batteries.