Preparation of N/O-codoped quinoline pitch-based porous carbons for high-quality supercapacitor electrodes

In order to create advanced carbon electrodes for supercapacitors, we selected a quinoline pitch (QLP) catalytically synthesized by a self-rising pressure method as a carbon precursor to prepare N/O-codoped high-capacity porous carbons by KOH high-temperature activation. The as-fabricated QLP-based porous carbons have hierarchical and interconnected pore structures rich in 2-10 nm small mesopores together with high surface N/O-doping contents (up to 3.69 at% N and 10.11 at% O), giving them excellent electrochemical performances. In particular, the porous carbon obtained at 700 degrees C can deliver impressive specific capacitances of 452 F g(-1) at 0.5 A g(-1) and 270 F g(-1) even at a high current density of 50 A g(-1) in 6 M KOH solution. Moreover, the assembled symmetric supercapacitor cell can output a high specific energy density of 11.86 W h kg(-1) at 5020.13 W kg(-1) and maintain an initial capacity retention of 91.48% after charging/discharging 10 000 cycles at 1 A g(-1). This work demonstrates a realistic path toward large-scale production of high-quality carbon electrode materials for supercapacitors starting from a quinoline monomer.

Automated summary

In this study, N/O-codoped high-capacity porous carbons were prepared by catalytically synthesizing a quinoline pitch (QLP) and then activating it with KOH at high temperature. These porous carbons exhibited excellent electrochemical performances with hierarchical and interconnected pore structures and high N/O-doping contents. They maintained high specific capacitances even under high current densities and showed good cycling stability.