Direct Modeling of the Interfacial Resistance in All‐Solid‐State Battery

ABSTRACT Interfacial reconstruction and its associated high resistance govern the performance of all‐solid‐state batteries (ASSBs). However, indirectly inferring interfacial potentials from bulk band alignments masks the true solid–solid electrochemistry, causing orders‐of‐magnitude discrepancies in predicting space‐charge layer (SCL) resistances and impeding interface screening. Herein, by traversing 310 distinct interfaces from ∼29,000 literatures, we develop a non‐empirical numerical procedure that directly maps lithium‑ion redistribution to interfacial resistance by integrating ligand‑field theory with the SCL model. Considering electric potential differences and intrinsic carrier properties during interfacial reconstruction via a modified ligand‐field splitting strength (MLFSS) descriptor yields unprecedented bridging between modeling and measurement, reducing predicted resistance discrepancies from over ten orders of magnitude to within two. On this basis, we resolve the highly system‐dependent controversy over oxide interfacial resistances by identifying extreme MLFSS disparities (>3.5 eV) as the decisive factor, while emphasizing ion‑intercalation sulfides (<0.2 eV) as cathodes for their intrinsic SCL suppression. The predictive capability of this tunable criterion is validated in an all‐sulfide V 0.5 Cr 1.5 S 4 /Li 10 GeP 2 S 12 /75% Li 2 S‐24% P 2 S 5 –1% P 2 O 5 /Li prototype. The resulting ultralow interfacial resistance of 8.8 Ω cm 2 ensures superior cycling stability at an active‐material energy density of 562 Wh kg −1 , establishing a practical paradigm for breaking the energy and kinetics trade‐off in ASSBs.