Mechanical‐Electrochemical Coupling Enables Pressure‐Informed Diagnosis and Interfacial Self‐Leveling in Sodium‐Ion Batteries

Sodium (Na)-ion batteries (NIBs) are attractive for sustainable energy storage because of the abundance and low cost of Na resources. However, their practical fast-charging operation is severely challenged by metallic Na plating, continuous interfacial degradation, and the associated safety risks. Here we establish a quantitative mechanical-electrochemical coupling framework that links macroscopic pressure signals with microscopic electrode reactions, enabling real-time and nondestructive diagnosis of Na plating in NIBs. On this basis, we develop an integrated diagnose-repair-utilize management strategy (DRUMS) that shifts battery management from passive warning to active intervention. Beyond early identification of hazardous metallic Na plating, DRUMS further induces dual-interfacial self-leveling by redirecting plated Na at the anode into an in situ Na source for reconstruction of the cathode interphase, while simultaneously eliminating unsafe metallic Na accumulation on the anode. This coupling-enabled strategy mitigates interfacial deterioration and markedly enhances the cycling stability of fast-charging NIBs. More broadly, this work provides a mechanistically guided strategy for dynamic interface management and offers a practical route toward safer and more durable fast-charging batteries.