High Capacitance Supercapacitors Based on Polypyrrole and Carbon Nitride Composites

Abstract

In this work, an one step green electrochemical synthesis of a supercapacitor with high performance and stability based on carbon nitride and polypyrrole is described. The new composite was easily obtained through the electrodeposition of polypyrrole on the surface of carbon nitride using an aqueous suspension. This material was fully characterized using both theoretical studies and experimental techniques. The sample showed a capacitance value of 810 F g-1 (at 0.2 A g-1), retaining 92% of its initial value after 6000 charge-discharge cycles. Furthermore, the composite material retains 75% of the capacitance compared to the data measured at 0.2 A g-1 ( 810 F g-1) and 9.0 A g-1 (610 F g-1). Finally, normalizing the capacitance considering only the polypyrrole mass it was found a capacitance value of 3029 F g-1. To explain these results, it was used impedance spectroscopy and DFT calculations. The computational experiments showed the formation of hydrogen bonds between the N-H of the polypyrrole and the π-system of the carbon nitride which stabilized the structures. Besides, a planarization effect could also be observed over the polypyrrole chains. Both results are supported by the experimental data collected from the impedance experiments.