Stable Lithium Storage in Nitrogen‐Doped Carbon‐Coated Ferric Oxide Yolk–Shell Nanospindles with Preserved Hollow Space

다국어 초록 (Multilingual Abstract)

Iron oxide (Fe2O3) is a promising anode material for next‐generation high‐energy lithium‐ion batteries owing to its high theoretical specific capacity, but it suffers from unstable electrochemistry, as represented by a significant volume variation upon (de)lithiation and unstable solid–electrolyte interface. To target these issues, a double‐coating synthetic route has been developed to prepare a yolk–shell‐structured γ‐Fe2O3/nitrogen‐doped carbon composite, in which spindle‐like γ‐Fe2O3 cores are encapsulated in the highly conductive carbon shell. Through precisely controlling the void space between the γ‐Fe2O3 core and the carbon shell, volume variation in γ‐Fe2O3 during (de)lithiation is well accommodated, while the composite maintains an intact and relatively dense structure, which stabilizes the solid–electrolyte interface and is beneficial for improving the practical energy density of the material. With a stabilized (de)lithiation electrochemistry and a synergistic storage effect between the two active components, the composite enables excellent lithium storage performance, in terms of reversible capacity, cycling ability, and rate capability.
Controlling the void: Nitrogen‐doped, carbon‐coated Fe2O3 yolk–shell nanospindle composites (γ‐Fe2O3@NC) are successfully synthesized through a facile double‐coating route (see figure). With a highly conductive coating and precisely controlled void space, the composite exhibits a high specific capacity, cycling stability, and excellent rate performance in prototype lithium half‐cells, and thus, is a promising anode candidate for use in lithium‐ion batteries.