Facile synthesis of petroleum-based activated carbons/tubular polypyrrole composites with enhanced electrochemical performance as supercapacitor electrode materials

Pitch-based activated carbon/tubular polypyrrole (ACPPy) composites with various tubular polypyrrole (T-PPy) contents are prepared as active electrode materials for supercapacitors. Examination of the morphology of the ACPPy composites by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) shows that T-PPy is deposited onto the surface of pitch-based activated carbons (ACs). As evidenced by cyclic voltammetry and galvanostatic charge/discharge tests, the addition of T-PPy to ACs s significantly improves the specific capacitance of the carbon electrode and consequently, the electrochemical performances of ACPPy composites for supercapacitors. The composite material has a high specific capacitance of 82.3 F g⁻¹, whereas the capacitance of the ACs electrode is only 43.13 F g⁻¹. Although supercapacitors using the ACPPy composite as an active electrode material exhibit an initial loss of capacitance owing to the instability of PPy, the specific capacitance after 1000 cycles stabilizes at a similar value.