Comparative evaluation of PPyNF/CoOx and PPyNT/CoOx nanocomposites as battery-type supercapacitor materials via a facile and low-cost microwave synthesis approach

Two nanocompisitees with different morphologies of polypyrrole nanofibers/cobalt oxide (PPyNF/CoO x ) and polypyrrole nanotubes/cobalt oxide (PPyNT/CoO x ) were successfully prepared via a rapid and cost-efficient microwave approach. The micromorphology, surface chemical and crystalline structure of the resultant samples were characterized by FT-IR, XRD , SEM and XPS . Besides, electrochemical performances of the as-produced nanocompisitees with different mass ratio, microwave powers and times were further investigated as a battery-type electrode materials for supercapacitors . It was found that the maximum capacitance of PPyNF/CoO x could reached up to 270C g −1 at 1 A g −1 , as well as with good cycling stability (almost nothing capacitance loss after 1000 cycles). Compared to PPyNF/CoO x , PPyNT/CoO x , showed a lower specific capacitance of 167.5C g −1 at the same current density. Surprisingly, the specific capacitance of PPyNT/CoO x could be further increased by 166% (278.4C g −1 at 1 A g −1 ) after 1200 cycles, and the cycling stability with nearly 105% of the initial capacitance could be achieved after 4000 cycles. Moreover, the asymmetric supercapacitor device based on the PPyNF/CoO x //active carbon showed a maximum gravimetric energy density of 24.22 Wh kg −1 and power density of 6.8 kW kg −1 , testifying its enormous potential for energy storage devices.