Ordered Mesoporous α-Fe2O3 (Hematite) Thin-Film Electrodes for Application in High Rate Rechargeable Lithium Batteries



Herein is reported the synthesis of ordered mesoporous α-Fe2O3 thin films produced through coassembly strategies using a poly(ethylene-co-butylene)-block-poly(ethylene oxide) diblock copolymer as the structure-directing agent and hydrated ferric nitrate as the molecular precursor. The sol–gel derived α-Fe2O3 materials are highly crystalline after removal of the organic template and the nanoscale porosity can be retained up to annealing temperatures of 600 °C. While this paper focuses on the characterization of these materials using various state-of-the-art techniques, including grazing-incidence small-angle X-ray scattering, time-of-flight secondary ion mass spectrometry, X-ray photoelectron spectroscopy, and UV–vis and Raman spectroscopy, the electrochemical properties are also examined and it is demonstrated that mesoporous α-Fe2O3 thin-film electrodes not only exhibit enhanced lithium-ion storage capabilities compared to bulk materials but also show excellent cycling stabilities by suppressing the irreversible phase transformations that are observed in microcrystalline α-Fe2O3.