New dual-anions FeS0.5Se0.5@NC porous nanorods as advanced electrode materials for wide-temperature sodium-ion half/full batteries

The new N-doped carbon wrapped porous FeS0.5Se0.5 nanorods (FeS0.5Se0.5@NC) have been rationally designed using the FeOOH nanorod as a reaction template, poly-dopamine as the carbon source, combined with the subsequent sulfuration and selenization process. Due to the cooperative effect of dual-anion guided hetero-structure, and the effective protection of highly conductive and uniform N-doped carbon layer, the FeS0.5-Se0.5@NC as the new anode materials for room-temperature sodium ion batteries demonstrates remarkable sodium storage properties. When the current density is 0.5 A g-1, the FeS0.5Se0.5@NC can deliver a satisfied specific capacity of 522.8 mAh g-1 over 100 loops. Even at 5 A g-1, it still shows outstanding long-period cycling stability (450 mAh g-1 for 220 cycles). It also displays prominent rate capability (242.65 mAh g-1 at 20 A g-1). Even at a low temperature, the FeS0.5Se0.5@NC still shows good sodium storage properties. Except for the half -cells, the full cells also exhibit good electrochemical performances. Furthermore, various kinetic analysis and reaction mechanism of FeS0.5Se0.5@NC are investigated to analyze the excellent sodium storage properties. The synthesis strategy of FeS0.5Se0.5@NC can be adopted to prepare the other kinds of double anionic metal chal-cogenides anode materials to explore the potential applications in different energy storage fields.

Automated summary

The N-doped carbon wrapped porous FeS0.5Se0.5 nanorods (FeS0.5Se0.5@NC) are successfully designed using FeOOH nanorods, poly-dopamine, sulfuration, and selenization processes. The FeS0.5Se0.5@NC exhibits remarkable sodium storage properties in room-temperature sodium ion batteries due to the cooperative effect of dual-anion guided hetero-structure and the protection of the N-doped carbon layer. It shows satisfied specific capacity, long-period cycling stability, and prominent rate capability, even at low temperatures.