ZnSe/SnSe Heterostructure Incorporated with Selenium/Nitrogen Co‐Doped Carbon Nanofiber Skeleton for Sodium‐Ion Batteries

Abstract Effective strategies toward building exquisite nanostructures with enhanced structural integrity and improved reaction kinetics will carry forward the practical application of alloy‐based materials as anodes in batteries. Herein, a free‐standing 3D carbon nanofiber (CNF) skeleton incorporated with heterostructured binary metal selenides (ZnSe/SnSe) nanoboxes is developed for Na‐ion storage anodes, which can facilitate Na + ion migration, improve structure integrity, and enhance the electrochemical reaction kinetics. During the carbonization and selenization process, selenium/nitrogen (Se/N) is co‐doped into the 3D CNF skeleton, which can improve the conductivity and wettability of the CNF matrices. More importantly, the ZnSe/SnSe heterostructures and the Se/N co‐doping CNFs can have a synergistic interfacial coupling effect and built‐in electric field in the heterogeneous interfaces of ZnSe/SnSe hetero‐boundaries as well as the interfaces between the CNF matrix and the selenide heterostructures, which can enable fast ion/electron transport and accelerate surface/internal reaction kinetics for Na‐ion storage. The ZnSe/SnSe@Se,N‐CNFs exhibit superior Na‐ion storage performance than the comparative ZnSe/SnSe, ZnSe and SnSe powders, which deliver an excellent rate performance (882.0, 773.6, 695.7, 634.2, and 559.0 mAh g −1 at current rates of 0.1, 0.2, 0.5, 1, and 2 A g −1 ) and long‐life cycling stability of 587.5 mAh g −1 for 3500 cycles at 2 A g −1 .