Decoding the Buried Interface: A Synergistic Framework for Mastering the Core Challenges of Solid‐State Batteries

All-solid-state batteries offer a significant advancement in energy density and safety compared to conventional lithium-ion battery technologies. However, their development is critically impeded by the complex instability of solid-solid interfaces. These buried junctions, governed by intricate chemical, electrochemical, and mechanical degradation processes, present substantial scientific challenges that cannot be effectively addressed by a single research methodology. This review emphasizes the crucial role of a synergistic paradigm that integrates computational simulations with advanced experimental characterization to overcome these significant interface issues. A conceptual framework is proposed that categorizes this synergistic approach into four hierarchical levels: Foundational, which validates essential material properties; Dynamic, which captures real-time interface evolution using operando techniques; Multi-Scale, which links atomic-scale changes to macroscopic failures; and Intelligent, which harnesses artificial intelligence and machine learning to accelerate discovery and enhance data analysis. Through detailed case studies, the vital role of this integated approach is demonstrated in elucidating ionic transport mechanisms, predicting interfacial reaction pathways, deconstructing the multiphysics of lithium-dendrite growth, and understanding chemo-mechanical failures in composite electrodes. It is concluded that this synergistic methodology is essential for transitioning from descriptive analysis to the predictive, rational engineering of stable, high-performance interfaces necessary for the next generation of energy storage systems.