Overcoming the Interface Bottleneck in Solid‐State Batteries: Electrolyte Design, Interface Engineering, and Computational Discovery

ABSTRACT All‐solid‐state batteries (ASSBs) with inorganic solid electrolytes promise to surpass the energy density and safety limits of lithium‐ion batteries, yet interfacial challenges impede their practical deployment. This review surveys three principal inorganic electrolyte families, oxide garnets (Li 7 La 3 Zr 2 O 12 ), sulfide argyrodites (Li 6 PS 5 X), and LGPS‐type conductors, and halides (Li 3 MX 6 ), through the unifying lens of interface science. We examine the three critical interfaces governing cell performance: the cathode‐electrolyte interface, where coatings must block mutual decomposition while enabling Li + transfer; the anode‐electrolyte interface, where lithium dendrite penetration stems from coupled mechanisms of void‐induced current focusing, grain‐boundary electronic leakage, and mechanical fracture; and grain boundaries, which act as both ionic bottlenecks and failure initiation sites. Engineering strategies for each interface are assessed. Computational methods from density functional theory to machine learning are surveyed as enablers of accelerated discovery. Finally, we highlight emerging paradigms including high‐entropy electrolyte engineering, closed‐loop AI‐driven discovery, and interface‐centric design, arguing that practical solid‐state batteries demand co‐optimization of electrolyte composition, interface architecture, and computational prediction within an integrated framework.