Carbon quantum dots reinforced polypyrrole nanowire via electrostatic self-assembly strategy for high-performance supercapacitors

Carbon quantum dots (CQDs) reinforced polypyrrole nanowire (PPy-NW) was constructed via electrostatic self-assembly strategy. The as-made CQDs/PPy-NW composite demonstrated superior electrochemical properties benefited from a dotted line structure with large specific area, more active sites and outstanding electronic conductivity. As the results, the CQDs/PPy-NW composite electrode displayed a specific capacitance of 306 F g−1 at a current density of 0.5 A g−1 and retained 66.8% capacitance when the current density increased by 80 times (from 0.5 to 40 A g−1). In addition, the as-fabricated symmetric supercapacitor was able to offer a large areal capacitance (248.5 mF cm−2 at 0.2 mA cm−2) and good rate capability, the supercapacitor still retained good cycling stability even at a high current density of 5 mA cm−2 (85.2% capacitance retention after 5000 cycles). In conclusion, the good electrochemical properties suggest a great potential of the CQDs/PPy-NW in the development of high-performance supercapacitor electrode materials.