Unraveling Interfacial Failure Challenges and Mitigation Strategies in Phosphorus-Based Sodium-Ion Batteries

Phosphorus-based anodes emerge as candidates for sodium-ion batteries (SIBs) but face acute interfacial instability driven by coupled mechanical-chemical degradation, including volume change, polyphosphide dissolution, and pronounced air-induced interfacial oxidation. This Review systematically examines the coupled mechanical-chemical failure mechanisms, covering both mechanical and chemical pathways, and discusses recent advances in interface engineering strategies. Two main approaches involving internal modification and external regulation are detailed to collectively enhance interfacial integrity, suppress irreversible reactions, and improve cycling stability, especially under extreme conditions. Finally, we outline the application potential and future research directions to accelerate the development of phosphorus-based anodes. This Review aims to provide critical guidance for rational interface design to enable practical implementation of phosphorus-based anodes in next-generation SIBs.