Nitrogen doped carbon nanowires prepared from polypyrrole nanowires for potential application in supercapacitors

• A direct carbonization method for preparation of carbon nanowires
• Specific surface area and XPS spectra synthesis
• Excellent capacitive performance of this carbon nanowires
• The two-electrode system shows a high energy density (13.2 Wh kg− 1) at 0.33 A g− 1.

We employ a direct carbonization method for preparation of nitrogen-doped carbon nanowires using polypyrrole nanowires as the carbon precursor. Microstructural characterization indicates that the specific surface area and nitrogen content of carbon nanowires depend strongly on the carbonization temperature. As the carbonization temperature increases from 650 °C to 950 °C (the molar ratio of pyrrole and hexadecyl trimethyl ammonium bromide is 3.4), the specific surface area of nitrogen doped carbon nanowires increases from 306.9 to 580.2 m2 g− 1; while, the nitrogen content decreases from 6.62 to 1.55 at.%. The carbonization temperature of nitrogen doped carbon nanowires is 750 °C, which strikes a balanced specific surface area (405.6 m2 g− 1) and nitrogen content (5.59 at.%), exhibiting excellent capacitance performance. It delivers a large specific capacitance of 207 F g− 1 at 1 A g− 1 in three electrode systems. It also shows good cycle stability (the capacitance retention of 98.5% over 5000 cycles) and high energy density (13.2 Wh kg− 1 at the current density of 0.33 A g− 1 and the voltage window of 0–1.5 V) in symmetric two-electrode systems. These features warrant a potential useful material for supercapacitors.