Spindle-shaped FeS2 enwrapped with N/S Co-doped carbon for high-rate sodium storage

Pyrite (FeS2) has been considered as an attractive anode material for sodium ion batteries (SIBs), which not only provided with high theoretical capacity but also has features of low cost, rich reserves and environmental benignity. However, the huge volume expansions during a charge/discharge process and unsatisfied conductivity of FeS2 lead to the rapid capacity fading. Herein, spindle-like double-component composites constructed with FeS2 core and nitrogen/sulfur co-doped carbon shell (FeS2@NSC) are synthesized successfully, which can act as efficient anode materials for SIBs. Consequently. the FeS2@NSC composites exhibit high specific capacity of 571.3, 528.6 and 475.9 mA h g−1 at the current density of 200, 500 and 1000 mA g−1 respectively after 100 cycles. The results demonstrate the strategy of components-structure designing can boost sodium-storage performances.