Nitrogen-Doped High Surface Area Porous Carbon Material Derived from Biomass and Ionic Liquid for High-Performance Supercapacitors

In this work, bioderived high surface area, porous activated carbons (ACs) are synthesized from dried Sterculia foetida (SF) fruit shells via KOH activation. Further, for high-performance supercapacitor (SC) application, the nitrogen-doped AC (NAC) has been derived by pyrolysis of a nitrogen-enriched ionic liquid (IL) and AC mixture. Herein, aprotic 1-ethyl-3-methyl-imidazolium dicyanamide ([EMIM][DCN]) IL is used as a nitrogen precursor. A series of NACs has been successfully developed by tuning the weight ratio of IL and AC. The optimized NAC (2:1) exhibits suitable graphitization degree, hierarchical micromesopores to ensure effective electrolyte diffusion, high surface area, and enhanced wettability. Further, in a three-electrode configuration, the NAC (2:1) electrode shows a high specific capacitance of 567 F g–1 at 0.5 A g–1. Moreover, a symmetric two-electrode SC device was constructed, providing excellent specific energy of 13 Wh kg–1 at 300 W kg–1. Overall, this study presents the positive aspects of an IL as a nitrogen precursor to synthesize high surface area NACs as a promising electrode material for SC applications.