Nitrogen‐Doped Hierarchical Porous Carbon Framework Derived from Waste Pig Nails for High‐Performance Supercapacitors

Abstract

Abstract In situ nitrogen‐doped hierarchical porous carbon was synthesized by using waste protein‐rich pig nails as precursors in a facile KOH activation method. The microstructure and electrochemical characteristics of the materials were investigated by tuning the amount of KOH. When the weight ratio of KOH to pig nails is 1 : 1, the obtained nitrogen‐doped hierarchical porous carbon (NHPC‐1) exhibits the largest specific surface area (2569 m 2 g −1 ) with interconnected porous network structure, which are beneficial to ion/electron storage and transfer. In addition, abundant nitrogen of 2.8 at % in the NHPC‐1 also contributes to the high electrochemical activity of the supercapacitor during the charging/discharging process. As a result, the NHPC‐1 electrode in the supercapacitor exhibits a high specific capacitance of 231 F g −1 at 1 A g −1 and superior retention of 98 % after 5000 cycles at 1 A g −1 in 6 M KOH electrolyte. Additionally, the assembled symmetric device based on NHPC‐1 exhibits a high energy density of 7 Wh kg −1 at a power density of 500 W kg −1 . Our study suggests that waste pig nails can act as low‐cost and renewable carbon precursors for high performance supercapacitor.