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

Herein is reported the synthesis of ordered mesoporous alpha-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 alpha-Fe2O3 materials are highly crystalline after removal of the organic template and the nanoscale porosity can be retained up to annealing temperatures of 600 degrees 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 alpha-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 alpha-Fe2O3.