Bimetallic Sulfide Sb2S3@FeS2 Hollow Nanorods as High-Performance Anode Materials for Sodium-Ion Batteries.

Constructing heterojunction and introducing interfacial interaction by designing ideal structures have the inherent advantages of optimizing electronic structure and macroscopic mechanical property. An exquisite hierarchical heterogeneous of bimetal sulfide Sb2S3@FeS2 hollow nanorods embedded into nitrogen-doped carbon matrix is fabricated by a concise two-steps of solvothermal method. The FeS2 interlayer bulges in-situ grow on the interface of hollow Sb2S3 nanorods within the nitrogen-doped graphene matrix, forming a delicate heterostructure. Such a well-designed architecture affords rapid Na+ diffusion and improves charge transfer at the heterointerfaces. Meanwhile, the strongly synergistic coupling interaction among the interior Sb2S3, interlayer FeS2, and external nitrogen-doped carbon matrix creates a steady nanostructure, which extremely accelerates the electronic/ion transport and effectively alleviates the volume expansion upon long cyclic process. As a result, the composite, as an anode material for sodium-ion batteries, exhibits superior rate capability of 537.9 mAh g-1 at 10 A g-1, excellent cyclic stability with 85.7 % capacity retention after 1000 cycles at 5 A g-1. Based on the density functional theory (DFT) calculation, the existing constructing heterojunction in this composite can not only optimize the electronic structure to enhance the conductivity, but also favor the Na2S adsorption energy to accelerate the reaction kinetics. The outstanding electrochemical performance sheds light on the strategy by rational designing of hierarchical heterogeneous nanostructure for energy storage applications.