Direct pyrolysis fabrication of N/O/S self-doping hierarchical porous carbon from Platycladus Orientali leaves for supercapacitor

To meet the growing market requirement for low-cost supercapacitor electrode materials, N/O/S self-doping hierarchical porous carbon is successfully fabricated by direct pyrolysis of platycladus orientalLeaves (POL). The obtained carbon material exhibits wide application prospects, because of simple and green-environmental technology, low-cost and satisfactory electrochemical properties, which avoided complex preparation routes and consumption of expensive chemical reagents in the traditional activation process. Under the optimum pyrolysis temperature (850 degrees C), the obtained POL-derived carbon (POL-850) possesses a high specific surface area (1140.2 m2g- 1), sheet-like hierarchical porous microstructure, and uniform ternary heteroatoms co-doping (O: 6.79 at.%; N: 3.45 at.% and S: 2.20 at.%). As an electrode material for supercapacitor, the specific capacitance of the POL-850 reaches 224.4 Fg- 1 of 0.5 Ag- 1and 156.0 Fg- 1 at 30 Ag-1, revealing excellent rate performance. The capacitance retention maintains 96.3 % after 10,000 consecutive charge-discharge cycles at 20 Ag-1, demonstrating superior cycling stability. Additionally, the assembled carbon-based symmetric supercapacitor device delivers a satisfied energy density of 11.0 Wh kg- 1 with the power density of 65 W kg- 1 and ultralong cycle-lifetime with 95.65 % capacitance retention after 10,000 charge/discharge cycles, while the Coulombic efficiency is retaining up to approximately 100 %. This work provides an easy and cost-effective way to rapidly prepare N/O/S co-doping hierarchical porous carbon for supercapacitors, which is very suitable for large-scale production.