Low‐Temperature Sodium‐Ion Batteries: Interfacial and Bulk Perspectives on Performance Limitations and Improvement Strategies

ABSTRACT Sodium‐ion batteries (SIBs) are attractive for low‐temperature energy storage because of their low cost and abundant resources. However, their low‐temperature performance still suffers from capacity decay, severe polarization, poor cycle stability, and increased sodium‐plating risk. Existing reviews have mainly discussed this issue from the perspectives of electrolyte systems or electrode materials. In contrast, this review summarizes recent advances in low‐temperature SIBs from interfacial and bulk perspectives. At the interface, the main limitations include deteriorated electrolyte transport, strengthened Na + desolvation barriers, solvation structure instability, and parasitic side reactions. In the bulk, sluggish solid‐state diffusion, stress accumulation, structural degradation, and sluggish phase transition kinetics further restrict electrochemical performance. On this basis, representative strategies are discussed from both perspectives, including solvation regulation, electrolyte optimization, additive design, artificial solid electrolyte interphase, surface coatings, lattice doping, pore‐structure engineering, nanostructuring, and diffusion‐path optimization. Their advantages and limitations are also highlighted. This review provides ideas for understanding the origins of low‐temperature performance limitations and for guiding the design of low‐temperature SIBs.