Oxygen and nitrogen co-doped porous carbons with finely-layered schistose structure for high-rate-performance supercapacitors

Heteroatom-doped porous carbons have currently been regarded as the promising materials for supercapacitors because of their outstanding contributions in Faradaic capacitance and electrolyte accessibility. In the present study, O/N co-doped porous carbons have been prepared by carbonization of ammonium citrate single precursor followed by KOH activation. The as-synthesized carbon (ACA-800) has a finely-layered schistose architecture together with a high surface O and N-containing functionalities (6.82 at.% O and 1.37 at.% N), a high micropore surface area (1522 m2 g−1) and a balanced mesopore surface area (1138 m2 g−1). Due to their synergistic effects, the ACA-800 electrode displays high-rate capacitive performance with specific capacitance of 297 F g−1 at 100 A g−1, at least 85% of its capacitance (349 F g−1) at 1 A g−1. Moreover, symmetric supercapacitor assembled with such ACA-800 exhibits high energy density of 25.5 W h kg−1 at 923 W kg−1 as well as excellent cycling stability (only 4% of capacitance loss after 10000 cycles with a cell voltage of 1.8 V at a current load of 2 A g−1). Considering the global abundance and low price of ammonium citrate, it can serve as a novel precursor for the mass production of O/N-enriched porous carbons for advanced supercapacitors.