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

Abstract

Abstract 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 KHCO 3 . 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 Na 2 SO 4 electrolyte. The good electrochemical performance makes NHPC‐800 a potential electrode material for supercapacitor.