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

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 Sb2Se3-WSe2 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 Sb2Se3/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.