Synthesis\nof a Sodium-Ion\nCathode Material Na<sub>3</sub>Fe<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>F with the Help\nof Fluorine Element

The development of cathode materials\nhas always been\none of the\nmost crucial areas of research in the field of sodium-ion batteries.\nSulfate-based polyanionic materials, known for their high working\nvoltage characteristics, have received widespread attention. In this\nwork, a fluoro-sulfate sodium-ion battery cathode material, Na<sub>3</sub>Fe<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>F modified with\ncarbon nanotubes, was developed using a low-temperature solid-state\nannealing method. This Na<sub>3</sub>Fe<sub>2</sub>(SO<sub>4</sub>)<sub>3</sub>F cathode exhibits an exceptionally high voltage of\n3.77 V, excellent discharge capacity (102 mAh/g at 0.1C), and good\nrate capability. This material broadens the research directions for\ncathode materials and holds promise as a foundation for the further\ndevelopment of high-performance sodium-ion batteries.