A High-Performance Supercapacitor Based on Nitrogen-Doped Porous Carbon Derived from Cycas Leaves

摘要

In this work, we proposed a new way to synthesize nitrogen-doped porous carbon materials. Nitrogendoped porous carbon materials were prepared using cycas leaves as the carbon source and urea as thenitrogen source. Namely, the dried cycas leaves were first burned at 300 °C and then activated by KOHcontaining urea at 700 °C. The prepared samples display high specific surface areas; the highest specificsurface area and largest total pore volumes are approximately 2628 m2 g-1 and 1.39 cm3 g-1, respectively.A supercapacitor made by nitrogen-doped porous carbon shows attractive capacitive performance.Taking CU2-700 as an example, its specific capacitance is 373 F/g at 0.5 A/g, and 89% specificcapacitance retention is reached after 10000 cycles in a three-electrode system. In addition, high specificcapacitances of 260 F/g at 0.5 A/g and 203 F/g at 10 A/g are obtained, and CU2-700 has excellent cyclingstability (85% specific capacitance retention after 10000 cycles at 5 A/g) in a two-electrode system.Furthermore, the energy density of the supercapacitor is approximately 9.13 W h/kg at 125 W/kg powerdensity in a two-electrode system. These results indicate that cycas leaves are a good biomass carbonmaterial for preparing high-performance supercapacitors.