High‐rate performance and super long‐cycle stability of Na 3 V 2 (PO 4 ) 3 cathode material coated by diatomic doped carbon

Abstract Na 3 V 2 (PO 4 ) 3 is considered as one of the most promising cathodes for sodium ion batteries due to its excellent thermal stability, long cycle life and high energy density. However, the inferior intrinsic electronic conductivity which brings about the poor rate capability and cycling performance hinders its commercial application. Herein, the S–N co‐doped carbon‐coated Na 3 V 2 (PO 4 ) 3 (NVP@SNC) has been synthesized to resolve the problem. The prepared NVP@SNC forms a hierarchical structure assembled with nanosheets, which is in favor of the electrolyte infiltration and shortening the Na + transmission distance. Numerous lattice defects can be induced in carbon layer by the co‐doped elements (S–N), which reduce the Na + diffusion energy barriers and provide adequate Na + migration channels, thus jointly boosting the Na + diffusion coefficient. Consequently, the NVP@SNC cathode shows a high reversible capacity with outstanding rate performance and super long‐cycle stability. When discharged at 2.0C, it delivers the capacity near to the theoretical value with a capacity retention of 88.7% after 400 cycles. Even if the current is as high as 50.0C, a high capacity of 58.6 mAh·g −1 has been released, and 41.4 mAh·g −1 has been remained after the super long cycling of 4000 circles. This study is expected to supply a new thought of developing high‐performance cathodes by diatomic doping for sodium ion battery.