Preparation of ZnCo-MOF/PPy/Ag2O ternary composites for high-performance flexible supercapacitors

Polypyrrole (PPy) is successfully polymerized on the surface of 1D columnar ZnCo-MOF using (NH4)2S2O8 and AgNO3 as co-oxidant of PPy. The redox agent alizarin red S (ARS) is then in-situ introduced to obtain ZnCo-MOF/PPy/Ag2O ternary composite materials. The structural analysis confirms the successful polymerization of PPy, the multifunctional effect of ARS and the catalytic oxidation of Ag to Ag2O. The MPA/Ag2O-4 ( the concentration of AgNO3 is 4 mM) electrode delivers a maximum specific capacitance of 420 F/g at 1 A/g. An asymmetric supercapacitor (ASC) assembled with MPA/Ag2O-4 and activated carbon demonstrates a wide potential window of 2 V, high area capacitance of 148 mF/cm2 at 0.5 mA/cm2. And the energy density of the device reaches 82.23 μW h cm−2 at a power density of 501.74 μW cm−2. And the 3 V LED light is successfully powered by assembling three ASCs in series. The excellent cycling stability (capacitance retention of 84.5% after 10000 cycles) and the outstanding flexibility (capacitance retention is basically unchanged after bending 180°) ensure the MPA/Ag2O-4 composite a promising candidate for flexible wearable and portable electronic devices.