Beyond Passivation: Designing Structurally Tailored Artificial Interphases for High‐Energy Lithium‐Based Anodes

The development of next‐generation high‐energy‐density lithium batteries increasingly relies on high‐capacity anodes, particularly lithium metal and high‐content silicon, to surpass the energy limits of conventional lithium‐ion batteries. Despite their exceptional theoretical capacities, both anodes undergo severe mechanical deformation during cycling, including localized strain and volumetric expansion, leading to repeated fracture of the Solid Electrolyte Interphase (SEI). The resulting interfacial instability accelerates electrolyte decomposition, active lithium loss, dendrite growth, and rapid capacity degradation. Although Artificial Solid Electrolyte Interphases (A‐SEIs) have emerged as a promising strategy to stabilize these interfaces, current designs primarily emphasize electrochemical stability while overlooking the mechanical and processing requirements that govern long‐term durability and industrial translation. This review presents a practical engineering framework that decouples chemical passivation from structural stability by integrating interfacial mechanics, transport characteristics, and manufacturing considerations. By consolidating experimental observations, critical strain limits, and dominant failure mechanisms across representative A‐SEI architectures, it establishes quantitative design principles and practical selection criteria for mechanically robust artificial interphases. These guidelines provide a design checklist for developing A‐SEIs that are chemically stable, mechanically resilient, and compatible with scalable battery manufacturing.