Flexible g‐C3N4 Enhancing Superior Cycling Stability of ZnFe2O4‐Fe2O3 Nanosheet Composites as High‐Capacity Anode Materials for Lithium‐Ion Batteries

Abstract For lithium‐ion batteries, iron‐based oxides are expected to be the next generation of anode materials because of their high theoretical capacity, environmental friendliness, and affordability. Although, like most transition metal oxides, iron‐based oxides suffer from poor electrical conductivity and cycling performance, volume expansion during charging and discharging, and easily agglomerated. g‐C 3 N 4 has a graphene‐like layered structure consisting of nitrogen‐linked C 6 N 7 repeating units. The abundant nitrogen content can improve the wettability of the electrode and electrolyte, thus improving the lithium charge transfer process, and secondly g‐C 3 N 4 is less expensive and easier to prepare than graphene. Here, we report composites with metal oxide nanosheets (ZnFe 2 O 4 −Fe 2 O 3 ) attached to softly curved g‐C 3 N 4 nanosheets. When used as an anode material for lithium‐ion batteries, after 300 cycles at the current density of 500 mA g −1 , ZFO‐Fe 2 O 3 /g‐C 3 N 4 offers the discharge specific capacity (1518.5 mAh g −1 ) and can still deliver 639.2 mAh g −1 at the high current density (10 A g −1 ). Due to the introduction of g‐C 3 N 4 alleviated the volume change of the electrode, shortened the diffusion distance of Li + and provided more reactive sites, resulting in excellent electrochemical performance of ZFO‐Fe 2 O 3 /g‐C 3 N 4 .