Pre‐sodiation Technology for Interface Engineering in Sodium‐ion Batteries: Progress, Challenges, and Future Directions

Pre‐sodiation technology has emerged as a pivotal strategy for compensating active sodium loss in sodium‐ion batteries (SIBs) during both initial charging and long‐term cycling, thereby significantly enhancing their electrochemical performance. While significant progress has been made in developing diverse pre‐sodiation methods, there remains a notable gap in systematic reviews addressing their specific impacts on battery interfacial layers. This review comprehensively analyzes the transformative role of pre‐sodiation in engineering interfacial layers, with focused attention on the solid electrolyte interface (SEI) and cathode electrolyte interface (CEI). Through detailed analysis of recent advances, we delineate the mechanisms through which pre‐sodiation modulates the chemical composition and structural organization of these critical interfaces, while concurrently suppressing detrimental side reactions. Furthermore, future challenges and research directions for pre‐sodiation technology were identified, offering valuable perspectives to accelerate the optimization and commercialization of SIBs.