Nanocrystal-constructed mesoporous CoFe2O4 nanowire arrays aligned on flexible carbon fabric as integrated anodes with enhanced lithium storage properties

Abstract

A novel and facile two-step strategy is successfully developed for the large-scale fabrication of hierarchical mesoporous CoFe₂O₄ nanowire arrays (NWAs) on flexible carbon fabric as integrated anodes for highly efficient and reversible lithium storage. The synthesis involves the co-deposition of uniform bimetallic (Co, Fe) carbonate hydroxide hydrate precursor NWAs on carbon fabric and subsequent thermal transformation to spinel CoFe₂O₄ without damaging the morphology. The as-prepared CoFe₂O₄ nanowires have unique mesoporous structures, which are constructed by many interconnected nanocrystals with sizes of about 15–20 nm. The typical size of the nanowires is in the range of 70–100 nm in width and up to several micrometers in length. Such a hybrid nanostructure electrode presented here not only simplifies electrode processing, but also promises fast electron transport/collection and ion diffusion, and withstands volume variation upon prolonged charge/discharge cycling. As a result, the binder-free CoFe₂O₄/carbon fabric composite exhibits a high reversible capacity of 1185.75 mA h g⁻¹ at a current density of 200 mA g⁻¹, and a superior rate capability. More importantly, a reversible capacity as high as ∼950 mA h g⁻¹ can be retained and there is no obvious decay after 150 cycles.