Activation‐Induced Surface Modulation of Biowaste‐Derived Hierarchical Porous Carbon for Supercapacitors

• Published in: ChemPlusChem (Weinheim, Germany) Germany), 2022-06, Vol.87 (6), p.e202200126-n/a
• Main Authors: Sharma, Pratigya, Singh, Deobrat, Minakshi, Manickam, Quadsia, Saleha, Ahuja, Rajeev
• Format: Article
• Language: English
• Subjects: activated carbon; biowaste; Carbon - chemistry; density functional theory; Electric Capacitance; Electrodes; Porosity; supercapacitors; wheat straw
• ISSN: 2192-6506; 2192-6506
• DOI: 10.1002/cplu.202200126

Wheat straw‐derived carbon from the Wheatbelt region in Western Australia was subjected to chemical activation in an electrolyte containing either acid or base treatment. The findings showed an increase in electron/hole mobility towards the interfaces due to the presence of different surface functional groups such as C−SOx−C and S=C in the carbon framework for acid activation. Likewise, the galvanostatic capacitance measured at a current density of 2 mA cm−2 in a three‐electrode configuration for acid‐activated wheat straw exhibited 162 F g−1, while that for base‐activated wheat straw exhibited 106 F g−1. An increase of 34.5 % more capacitance was achieved for acid‐treated wheat straw. This improvement is attributed to the synergistic effects between surface functional groups and electrolyte ions, as well as the electronic structure of the porous electrode. Hierarchically porous carbon materials derived from bio‐waste with desired surface functional groups are attractive for electrochemical applications. Both acid and base activating reagents are harnessed to modulate the electrode‐electrolyte interface relevant to electrochemical supercapacitors in satisfying structural, electronic, and electrochemical properties together. This study helps to understand molecular‐level tailoring of various activating reagents to tune the electronic properties for energy storage.