Highly active N,O-doped hierarchical porous carbons for high-energy supercapacitors

Highly active N,O-doped hierarchical porous carbons（NOCs） are fabricated through the in-situ polymerization and pyrolysis of o-tolidine and p-benzoquinone.As-prepared NOCs have a variety of faradaic-active species（N-6,N-5 and O-I）,high ion-accessible platform（1799 m;/g） and hierarchically micro-meso-macro porous architecture.Consequently,the resultant NOC electrode delivers an advantageous specific capacitance（311 F/g）,with a pseudocapacitive contribution of 37% in a threeelectrode configuration,and an enhanced energy output of 18.0 Wh/kg@350 W/kg owing to the enlarged faradaic effect in an aqueous redox-active cell.Besides,a competitive energy density（74.9 Wh/kg） and high-potential durability（87.8%） are achieved in an ionic liquid（EMIMB F4）-assembled device.This study sheds light on a straightforward avenue to optimize the faradaic activity and nanoarchitecture for advanced supercapacitors.