Graphitic Carbon-Doped Mesoporous Fe₂O₃ Nanoparticles for Long-Life Li-Ion Anodes

Abstract

Biomass\ncarbon-coated and pseudocapacitance-assisted α-Fe₂O₃ has recently gained more attention for enhanced\nlithium storage performance. Herein, we used a waste poplar branch\nas a biotemplate and a carbon source to prepare graphitic-C-doped\nmesoporous α-Fe₂O₃ (α-Fe₂O₃/C) through a simple immersion–carbonization–calcination\nmethod. The influence of carbon content on both the microstructures\nand electrochemical properties was also studied. The product calcined\nin air at 400 °C (Fe₂O₃/C₄₀₀) presents a hierarchically tubular structure with cross-linkage\nof 18% graphitic-C and α-Fe₂O₃ nanoparticles\nwith an average size of ∼28 nm. Meanwhile, the Fe₂O₃/C₄₀₀ nanomaterial exhibits a large surface\narea of 114 m² g^–1 and mesopore size\ndistribution centered at 2 nm. As lithium-ion battery anode material,\nsuch a unique hierarchical structure presents a certain pseudocapacitance\nbehavior, thus improving its lithium storage performance. Electrochemical\nmeasurements show that the Fe₂O₃/C₄₀₀ nanomaterial exhibits higher specific capacity and better rate performance.\nEspecially, it can retain a capacity of 885 mA h g^–1 at 1 A g^–1 after cycling 1400 times, indicating\ngood capacity retention and long-cycling stability. The good electrochemical\nperformance mainly originates from the synergism of the unique microstructure\nof the Fe₂O₃/C₄₀₀ nanomaterial, suitable\ndoping of graphitic-C, and certain pseudocapacitance behavior. Thus,\nthe low-cost bifunctional biotemplate strategy can provide a useful\nexperience for the massive synthesis of pseudocapacitance-assisted\nhigh-performance anodes.