Polyurethane foam derived nitrogen-enriched porous carbon/reduced graphene oxide composite with sandwich-like nanoarchitectures for supercapacitors

A new type of polyurethane (PU) foam derived nitrogen-enriched porous carbon/reduced graphene oxide (PU/rGO) composite was synthesized and studied for the first time. By taking advantages of PU foam as carbon skeleton precursor, GO nanosheets wrapped onto the skeleton’s surface through hydrothermal process, then the stable porous sandwich-like nanoarchitectures built after carbonization process. Moreover, the wrapped GO can be transformed into rGO due to thermal reduction during the carbonization process. When being applied as supercapacitor electrodes, the prepared PU/rGO composite could achieve an extremely high specific capacitance of 490 and 341.7 F g−1 at a current density of 1 and 20 A g−1, respectively. After 5000 cycles, the specific retention yielded to 97.3% at 1 A g−1. Resulting from these merits, the as-assembled symmetric supercapacitor device with a wide operating voltage window of 1.5 V exhibit an excellent energy density of 21.66 Wh kg−1 at a power density of 825 W kg−1 and remain 7.5 Wh kg−1 even at a high power density of 2250 W kg−1. Most importantly, this work may offer a strategy for converting the PU foam wastes into carbon material with excellent electrochemical performance applied on energy storage.