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 m(2) g(-1)) and a balanced mesopore surface area (1138 m(2) 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. (C) 2017 Elsevier Ltd. All rights reserved.