Phase-Reconstructable MoS ₂ Heterostructures for High-Performance Sodium-Ion Batteries

The practical application of sodium-ion batteries is hindered by slow ion transport and structural degradation of anodes during cycling. To address this, we report an iodine-doped MoS 2 heterostructure with carbon intercalation (I-MoS 2 @C), constructed via an in situ hydrothermal strategy that integrates phase engineering with interfacial modulation. Glucose-derived carbon layers confine reversible 2H-1T phase transformations, enhancing structural adaptability and ion transport. Concurrently, electron transfer from iodine stabilizes the 1T phase, improving Na + adsorption and electronic conductivity. At the interface, I–C catalytic sites promote fluorine release and the formation of a NaF-rich SEI, strengthening interfacial ion kinetics and stability. As a result of these synergistic effects, the I-MoS 2 @C anode exhibits high-rate capability (220 mAh g –1 at 20 A g –1 ) and exceptional cycling durability. This work demonstrates a strategy for designing dynamically reconstructable, interface-optimized heterostructures for high-performance sodium-ion storage.