Thin-film interlayer architectures for superior all-solid-state battery performance

This review comprehensively examines functional thin-film interlayers that play a pivotal role in advancing all-solid-state battery (ASB) technology by stabilizing solid–solid interfaces, enhancing ionic conductivity, and suppressing dendrite formation. It systematically discusses metal-based, non-metallic, and composite interlayer materials, correlating their physicochemical characteristics with electrochemical performance. Emerging deposition strategies, including atomic layer deposition, chemical vapor deposition, and additive manufacturing, are analyzed with respect to coating uniformity, scalability, and structural compliance. Computational approaches—such as density functional theory (DFT), molecular dynamics (MD), and finite element analysis (FEA)—are highlighted for their ability to predict interfacial behavior, guide material selection, and accelerate design optimization. The review also explores cross-chemistry applicability of these interfacial strategies to non-lithium systems, including Na-, Mg-, and Zn-based ASBs. Finally, recent innovations, current limitations, and prospects for scalable fabrication are summarized, providing a unified mechanistic perspective toward the development of durable, high-performance, and sustainable solid-state energy storage systems.