Hierarchical Fe3O4@C nanofoams derived from metal-organic frameworks for high-performance lithium storage

A facile method was employed to in situ prepare hierarchical mesoporous FeO@C nanofoams through pyrolysis of a post-treated MIL-53(Fe) precursor.Welldefined carbon network-encapsulated ultrasmall and uniform FeOoctahedrons can be obtained by controlling the pyrolysis temperature.This unique artificial shows the excellent lithium storage performance.A reversible discharge capacity of 861.9 mAh·gis observed at 0.1 A·gafter 300 cycles.Even at a high current density of 1 A·g,the reversible discharge capacity can still reach 605.2 mAh·gafter 500 cycles.Good rate capability is also observed,as the specific discharge capacities are833.6,729.9,666.8,643.6 and 635.6 mAh·gat current density of 0.2,0.5,0.8,1.0 and 1.2 A·g,respectively.The attractive electrochemical performance of FeO@C nanofoams should be attributed to the hierarchical foamlike structure,which can effectively relieve the volume change during the lithiation/delithiation process and facilitate fast lithium-ion and electron transport.