MOF-derived Fe3O4 hierarchical nanocomposites encapsulated by carbon shells as high-performance anodes for Li-storage systems

Abstract Transition-metal oxides are widely regarded as promising anode materials for lithium-ion batteries (LIBs). However, they suffer from rapid capacity damping which arises from significant volume expansion and poor conductivity during charge-discharge processes. Herein, the metal-organic framework (MOF) derived hierarchical Fe3O4@C nanocomposites coated with carbon were successfully fabricated. Three kinds of Fe-MOF templates with various morphologies were constructed and then carbonized to obtain the corresponding hierarchical Fe3O4@C nanocomposites. Benefiting from the hierarchical core-shell structure, the obtained Fe3O4@C nanocomposites exhibit outstanding electrochemical performance in LIBs. Specifically, the electrodes presented impressive cycling performance (990, 800, and 1180 mAh g-1 after 100 cycles) and outstanding rate stability. Additionally, the Li-storage conversion mechanism and the functional mechanism of coated carbon were identified with in situ electrochemical impedance spectra. This work provides a facile MOF-derived route to design anode materials with a high specific capacity in the energy storage field.