Bilayer N-doped carbon derived from furfuryl alcohol-wrapped melamine sponge as high-performance supercapacitor

Bilayer carbon is synthesized via carbonization of furfural alcohol-wrapped melamine sponge. Such materials combine the merits of carbonized furfuryl alcohol and melamine sponge: melamine sponge-derived three dimensional N-doped carbon serves as skeleton and support to avoid the agglomeration of furfuryl alcohol; while the furfuryl alcohol coating enhances the carbon yield, avoids the nitrogen loss of melamine sponge and introduces the second carbon layer. Carbonized furfuryl alcohol-wrapped melamine sponge shows the highest specific capacitance of 184 F g−1 at the scan rate of 5 mV s−1, which is almost four times that of carbonized melamine sponge without furfuryl alcohol coating (47.3 F g−1 at 5 mV s−1). Based on the electrochemical measurements, it suggests that the nitrogen content, especially the quaternary nitrogen content and the graphitization degree of carbon are two key dominant factors in enhancing the capacitive performance after furfuryl alcohol coating.