Rational fabrication of CoS2/Co4S3@N-doped carbon microspheres as excellent cycling performance anode for half/full sodium ion batteries

Cobalt sulfides have attracted tremendous attention as promising anodes for sodium-ion batteries owing to their low cost, rich types and high theoretical specific capacity. However, the design and application of cobalt sulfides with long cycling stability and high capacity still remains a great challenge. Herein, CoS2/Co4S3@N-doped carbon (CoS2/Co4S3@NC) microspheres obtained via a simple solvothermal and subsequent annealing approach were investigated as an advanced anode material for sodium-ion batteries. It delivers excellent rate capability (650 mAh g−1 at 0.3 A g−1, and 217 mAh g−1 at 6 A g−1) and ultralong-term cycling performance (256 mAh g−1 after 1500 cycles at 4 A g−1, and 239 mAh g−1 after 3000 cycles at 6 A g−1). The extraordinary electrochemical performance of the present material as anode for SIBs was believed to arise from the unique structure advantages of the composite and the good combination as well as the synergistic effects among the components. In addition, FeFe(CN)6//CoS2/Co4S3 full cell was assembled and delivered a reversible capacity of 520 mAh g−1 at 500 mA g−1. This work may provide new directions for constructing promising high-performance SIBs electrodes for electrochemical energy storage.