Preparation and electrochemical properties of nanofiber poly(2,5-dihydroxyaniline)/activated carbon composite electrode for supercapacitor

In this study, poly(2,5-dihydroxyaniline) (PDHA) was successfully prepared by electrochemical method on the surface of active carbon (AC) electrodes. The physical and electrochemistry properties of PDHA/AC composite electrode compared with pure AC electrode were investigated by scanning electronic microscope (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy, cycle life test. From SEM, PDHA presents nanofiber network morphology. The diameter of the nanofiber PDHA is about 200–300 nm. PDHA/AC composite electrode shows redox peaks in CV curve and voltage plateaus in galvanostatic charge–discharge curve, and all these indicate that PDHA/AC composite electrode has more advantages. The maintenance of the capacitance compared to initial cycle capacitance of composite electrode is about 90% during the charge–discharge cycles. In conclusion, The PDHA/AC composite electrode shows much higher specific capacitance (958 F g⁻¹), better power characteristics, longer cycle life. Therefore, PDHA/AC composite electrodes were more promising for application in capacitor. This can be attributed to the introduction of nanofiber PDHA. The effect and role of PDHA in the composite electrodes were also discussed in detail.