Carbon-coated Fe 2 O 3 hollow sea urchin nanostructures as high-performance anode materials for lithium-ion battery

Fe 2 O 3 has become a promising anode material in lithium-ion batteries (LIBs) in light of its low cost, high theoretical capacity (1007 mA h g −1 ) and abundant reserves on the earth. Nevertheless, the practical application of Fe 2 O 3 as the anode material in LIBs is greatly hindered by several severe issues, such as drastic capacity falloff, short cyclic life and huge volume change during the charge/discharge process. To tackle these limitations, carbon-coated Fe 2 O 3 (Fe 2 O 3 @MOFC) composites with a hollow sea urchin nanostructure were prepared by an effective and controllable morphology-inherited strategy. Metal-organic framework (MOF)-coated FeOOH (FeOOH@-MIL-100(Fe)) was applied as the precursor and self-sacrificial template. During annealing, the outer MOF layer protected the structure of inner Fe 2 O 3 from collapsing and converted to a carbon coating layer in situ. When applied as anode materials in LIBs, Fe 2 O 3 @MOFC composites showed an initial discharge capacity of 1366.9 mA h g −1 and a capacity preservation of 1551.3 mA h g −1 after 200 cycles at a current density of 0.1 A g −1 . When increasing the current density to 1 A g −1 , a reversible and high capacity of 1208.6 mA h g −1 was obtained. The enhanced electrochemical performance was attributed to the MOF-derived carbon coating layers and the unique hollow sea urchin nanostructures. They mitigated the effects of volume expansion, increased the lithium-ion mobility of electrode, and stabilized the as-formed solid electrolyte interphase films.