Coal tar

Catalysis

Composite number

Engineering

Capacitance

Pseudocapacitance

Materials science

Nanosheet

In situ

Carbon fibers

Chemical engineering

Coal

Porosity

Physical chemistry

Supercapacitor

Nanotechnology

Organic chemistry

Doping

Composite material

Chemistry

Electrode

Optoelectronics

Specific surface area

Electrochimica Acta

N-doped porous carbon nanosheets (N-CNS) were prepared from coal tar pitch with the addition of urea and KOH activation. In the synthesis route, urea plays an important role in constructing the 2D sheet-like structure, which serves as a nitrogen source, chemical blowing agent and the in-situ formation of g-C3N4 self-degraded template. At a low activation temperature (600 °C), the as-prepared N-doped porous carbon nanosheets possess high nitrogen content (7.06 at. %) and high specific surface area (1181 m2 g−1), which offers remarkable capacitive performances due to the unique architecture and pseudocapacitance contribution of the N doping. The N-CNS exhibits high capacitive performance (210 F g−1 at 0.1 A g−1), and an excellent cycling stability. Additionally, the assembled symmetric supercapacitor displays an energy density of 7.15 Wh kg−1, and the capacitance retention remains 91.2% after 5000 cycles at 1 A g−1. The facile and low-cost route to massively prepare N-doped porous carbon nanosheets from coal tar pitch would be favorable to the applications of carbon materials for high performance supercapacitors.

Coal tar pitch derived N-doped porous carbon nanosheets by the in-situ formed g-C3N4 as a template for supercapacitor electrodes