Nitrogen-Doped High Surface Area Porous Carbon Material Derived from Biomass and Ionic Liquid for High-Performance Supercapacitors
Sumana Brahma, Kothandaraman Ramanujam, Ramesh L. Gardas
Abstract
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.