Synthesis and electrochemical properties of Fe3O4@MOF core-shell microspheres as an anode for lithium ion battery application

The Fe 3 O 4 @MOF composite with a microspheric core and a porous metal-organic framework (MOF HKUST-1) shell has been successfully synthesized utilizing a versatile Layer-by-Layer (LBL) assembly method. The structure was identified by X-ray diffraction (XRD), and the morphology was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The Fe 3 O 4 @MOF composite exhibited outstanding electrochemical properties when it was used as an anode material for lithium ion batteries (LIBs). After 100 discharge-charge cycles at a current density of 100   mA   g −1 , the reversible capacity of Fe 3 O 4 @MOF could maintain ∼1002   mAh   g −1 , which was much higher than that of the bare Fe 3 O 4 counterpart (696   mAh   g −1 ). Moreover, load the current density as high as 2   A   g −1 (after 70 cycles at the current density step increased from 0.1 to 2   A   g −1 ), it still delivered a reversible capacity of ∼429   mAh   g −1 . The results demonstrate that the cycling stability of Fe 3 O 4 as an anode could be significantly improved by coating Cu 3 (1,3,5-benzenetricarboxylate) 2 (HKUST-1). This strategy may offer new route to prepare other composite materials using different particles and suitable Metal-organic frameworks (MOFs) for LIBs application.