In Situ Phase Transformation to form MoO3−MoS2 Heterostructure with Enhanced Printable Sodium Ion Storage

Abstract Molybdenum trioxide (MoO 3 ) possesses high energy density but often suffers from poor electrical conductivity and limited cycling stability when used as a sodium‐ion battery (SIB) anode. To address these issues, the construction of （Molybdenum trioxide‐Molybdenum disulfide）MoO 3 ‐MoS 2 heterostructures has proven effective in enhancing electronic conductivity, ion diffusion properties, and structural stability. Guided by the density functional theory (DFT) calculations, which predict favorable Na+ diffusion and adsorption properties, nanorod‐like MoO 3 ‐MoS 2 heterostructures are synthesized using a two‐step method. Benefiting from the synergistic effects of the heterostructure and nanosized morphology, the resulting MoO 3 ‐MoS 2 electrode exhibits outstanding rate performance (316 mA h g −1 at 10 A g −1 ) and long‐lasting cycling stability (286 mA h g −1 after 2300 cycles at 5 A g −1 ) as an SIB anode. In situ XRD measurements reveal that the ultrahigh specific capacity of MoO 3 ‐MoS 2 is attributed to the synergistic intercalation‐conversion storage of MoO 3 and MoS 2 . In the pursuit of meeting commercialization requirements, electrodes with adjustable mass loading are also prepared using 3D printing, showcasing the high areal capacity characteristics of the SIBs. This study not only provides theoretical insights into expanding the use of heterojunction materials as SIB anodes but also demonstrates the significant potential for creating high‐energy‐density and cost‐effective SIBs.