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

When used as lithium-ion batteries (LIBs) anode, ZFO-Fe₂O₃/g-C₃N₄ offers discharge specific capacity of 1518.5 mAh g⁻¹ after 300 cycles at the current density of 500 mA g⁻¹ and can still reach 639.2 mAh g⁻¹ at high current density of 10 A g⁻¹.

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-C₃N₄ has a graphene-like layered structure consisting of nitrogen-linked C₆N₇ 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-C₃N₄ is less expensive and easier to prepare than graphene. Here, we report composites with metal oxide nanosheets (ZnFe₂O₄−Fe₂O₃) attached to softly curved g-C₃N₄ nanosheets. When used as an anode material for lithium-ion batteries, after 300 cycles at the current density of 500 mA g⁻¹, ZFO-Fe₂O₃/g-C₃N₄ 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-C₃N₄ 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-Fe₂O₃/g-C₃N₄.

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