Low-cost high-performance asymmetric supercapacitors based on Co2AlO4@MnO2 nanosheets and Fe3O4 nanoflakes

The development of portable and wearable electronics has promoted the increasing demand for high-performance power sources with high energy/power density, low cost, lightweight, as well as ultrathin and flexible features. Herein, a low-cost high-performance flexible asymmetric supercapacitor (ASC) with Co2AlO4@MnO2 nanosheets and Fe3O4 nanoflakes grown on nickel foam is designed and fabricated. The as-designed ASC device with an extended operating voltage window of 1.6 V achieves a specific capacitance of 99.1 F g(-1) at a current density of 2 A g(-1) with a maximum energy density of 35.3 W h kg(-1) and very long-term cycling stability (92.4% capacitance after 5000 cycles).