Supercapacitor with high cycling stability through electrochemical deposition of metal-organic frameworks/polypyrrole positive electrode

Electrochemical deposition is an environment-friendly method for functional film fabrication, benefiting from the facile tuning of structure and properties of the film. Metal-organic frameworks (MOFs) play a significant role in the field of energy sources because of their porous nature, large specific surface area and metal ion binding sites. However, the application of such materials is limited by their inherent insulator-like characteristics and poor electrical conductivity. In this study, we designed and fabricated a composite material comprising metal-organic framework/polypyrrole as the positive electrode of a supercapacitor via smear and electrodeposition methods. Electrochemical properties of the electrode materials were studied through galvanostatic charge/discharge (GCD) and cyclic voltammetry (CV) tests. The positive electrode has an excellent specific capacitance of 284.3 F g −1 (180.7 mF cm −2 ) with 1 mA cm −2 current density. Furthermore, this material as a positive electrode shows high cycling stability after 40 000 cycles (100.7% capacitance retention). This strategy can be extended to fabricate other MOFs and MOFs/conducting polymers composite electrodes for supercapacitors. Through electrochemical deposition, a novel positive electrode comprising ZIF-67 and polypyrrole, showing ultrahigh cycling stability (100.7%, 40 000 cycles), was fabricated.