Ultrathin defect-rich nanosheets of NiFe-MOF with high specific capacitance and stability for supercapacitor

Ni-MOF shows high specific capacitance and rate capability performance as supercapacitor cathode, but it still exhibits poor intrinsic conductivity and cycle stability. Herein, we explore a bind free structural stabilized NiFe-MOF on nickel foam via one-pot solvothermal method for high performance supercapacitor. Various characterization results reveal that the prepared NiFe-MOF is composed of defective ultrathin nanosheets. The incorporation of Fe ions nodes can not only enhance the Ni-MOF cycle stability, but also increase the specific capacitance attributed to the formation of defects. The optimized NiFe-MOF exhibits an ultra-high specific area capacitance (15.6 F cm−2 at 2 mA cm−2) with excellent cycle stability (86.3 % cycle retention rate in 5000 cycles at 50 mA cm−2) in 1 mol L−1 KOH. The asymmetric supercapacitor (ASC) device constructed by NiFe-MOF/NF cathode and activated carbon (AC) anode achieves a high energy density of 0.75 mWh cm−2 and a power density of 8.0 mW cm−2. Our work provides an important strategy for the designing of high-performance energy storage material.