A Novel Ultrastable and High-Performance Electrode Material for Asymmetric Supercapacitors Based on ZIF-9@Polyaniline

Nanoflower-like composites have greater contact area and more redox reactive centers, which have great potential in the application of electrode materials for supercapacitors. A nonconductive polymer binder is usually used in preparation of electrodes, which causes an increase in interface resistance and a decrease in material active sites. Here, polyaniline (PANI) and ZIF-9 are directly grown on the Ni foam (ZIF-9@PANI/NF) by a simple solvothermal method without a nonconductive polymer binder. A nanoflower array is grown on the NF, which can be directly used as electrode material of supercapacitor. The attachment of PANI facilitates electron transfer and increases the conductivity of the material. At a current density of 1 A g(-1), the specific capacitance is up to 7 times that of the ZIF-9. The assembled asymmetric supercapacitor has a high energy density of 52 Wh kg(-1) at a power density of 800 W kg(-1), remaining 90.1% after 50 000 cycles. These great electrochemical properties show the material has good market development prospects for energy storage device.