Facile synthesis of Fe-based metal-organic framework and graphene composite as an anode material for K-ion batteries

We have reported an iron-based metal-organic framework (MOF-235) and graphene composite as a suitable anode host in the upcoming K-ion batteries. The bulk MOF-235 delivers poor K-storage performance and large electrochemical polarization due to its inherent poor electronic conductivity. Accordingly, a modified hydrothermal reaction was performed to contrast a MOF-235 and graphene (G) composite and the as-prepared MOF-235+20G composite could deliver a remarkable capacity of 180 mAh/g over 200 cycles at a current density of 200 mA/g. Due to the addition of the two-dimensional layered conductive graphene, the electronic conductivity of the composite could be significantly improved. And the MOF-235 single crystal can be evenly embedded in the surface or interlayer of graphene to prevent the agglomeration phenomenon of the active material. Furthermore, the active material can be fully utilized during charging and discharging processes which is more conductive to the rapid transport of K+ and electron.