Tobacco-Stem-Derived Nitrogen-Enriched Hierarchical Porous Carbon for High-Energy Supercapacitor

Nitrogen enriched hierarchical porous carbons with high specific surface (SSA) area and well-connected pore structure are highly desirable for supercapacitor electrode materials. Herein, nitrogen enriched hierarchical porous carbon (NHPC) was prepared by pre-carbonization of tobacco stems and activation by KHCO3. The as-prepared NHPC-800 exhibits high SSA (2691 m(2) g(-1)) and high proportion of mesopore (76.5 %). NHPC-800 also shows high nitrogen content of 1.4 %. Benefited from improved pore structure and chemical composition, the obtained NHPC-800 delivered a high capacitance of 252.9 F g(-1) at 0.5 A g(-1) and 189.1 F g(-1) at 20 A g(-1) in 6 M KOH. Additionally, the symmetric supercapacitor exhibits a high energy density of 7.8 W h kg(-1) and good cycle stability with 92.6 % capacitance retention after 6000 charge/discharge cycles in 1 M Na2SO4 electrolyte. The good electrochemical performance makes NHPC-800 a potential electrode material for supercapacitor.

Automated summary

Nitrogen enriched hierarchical porous carbon (NHPC) with high specific surface area and well-connected pore structure was successfully prepared by pre-carbonization of tobacco stems and activation by KHCO3. The obtained NHPC-800 exhibited a high nitrogen content, optimized pore structure, and chemical composition, delivering excellent electrochemical performance as a potential electrode material for supercapacitors.