FeO_0.7F_1.3/C Nanocomposite as a High‐Capacity Cathode Material for Sodium‐Ion Batteries

Abstract

Searching high capacity cathode materials is one of the most important fields of the research and development of sodium‐ion batteries (SIBs). Here, we report a FeO 0.7 F 1.3 /C nanocomposite synthesized via a solution process as a new cathode material for SIBs. This material exhibits a high initial discharge capacity of 496 mAh g −1 in a sodium cell at 50 °C. From the 3 rd to 50 th cycle, the capacity fading is only 0.14% per cycle (from 388 mAh g −1 at 3 rd the cycle to 360 mAh g −1 at the 50 th cycle), demonstrating superior cyclability. A high energy density of 650 Wh kg −1 is obtained at the material level. The reaction mechanism studies of FeO 0.7 F 1.3 /C with sodium show a hybridized mechanism of both intercalation and conversion reaction.