Algae-Derived Nitrogen Self-Doped Porous Carbon Materials with High Supercapacitor Performances

The design of carbon materials with high electrochemical performances is desirable to fulfill the demands of next-generation supercapacitors. In this study, porous nitrogen-doped carbon materials were prepared by hydrothermal carbonization and KOH activation using a renewable algae as the nitrogen source and partly carbon source. Addition of glucose as a promoter was found to favor the formation of homogeneous spherical structure and retention of nitrogen in the solid phase, resulting in excellent capacitive properties. Under optimized conditions, the algae-derived nitrogen self-doped porous carbon materials had a high specific surface area of 1893.26 m2/g, a high nitrogen content of 2.9 wt %, and a large gravimetric capacitance of 335.5 F/g in a 6 M KOH aqueous electrolyte. After 5000 cycles, the assembled supercapacitor still maintained 89.41% of the initial capacitance, demonstrating a good cycling stability. The results indicated that renewable algae could be a promising nitrogen source for the production of N-doped carbon materials.