Carbon Mediated Multifunctional Sb2Se3–WSe2 Heterostructure Nanofiber Facilitates Rapid and Stable Na+ Transport

Abstract Alloying metal selenides as advanced anode materials for sodium‐ion devices requires overcoming the challenges of high diffusion energy barriers and large volume expansion at high‐power densities. The typical dealloying process is difficult to trigger under fast kinetics, leading to limited capacity utilization. Here, Sb/W‐hybridization precursor is synthesized by one‐step reaction, followed by electrostatic spinning strategy to achieve a localized domain‐limiting effect. Finally, the carbon mediated Sb 2 Se 3 –WSe 2 heterostructure nanofiber (SbWSe/C/NF) are obtained after carbonization/selenization process. Physical characterization and theoretical calculations reveal that the SbWSe/C/NF‐500 has a heterogeneous structure and abundant edge carbon defects, facilitating rapid Na + transfer from exterior to interior. Furthermore, compared with the Sb 2 Se 3 /C monomer, the SbWSe/C heterostructure shows a significant dealloying reaction at high current densities, enhancing capacity utilization. Resultantly, the Na half‐cell with SbWSe/C/NF‐500 electrode demonstrates excellent rate capability and a high specific capacity of 553.7 mA h g −1 after 250 cycles at 2 A g −1 . Meanwhile, the assembled sodium‐ion capacitor exhibits 80.83% capacity retention after 8000 cycles at 3800 W kg −1 . The structure design strategy of cationic heterostructures with dual‐carbon introduction provides a reference for developing high‐power anodes.