Hierarchical porous carbon/Kraft lignin composite with significantly improved superior pseudocapacitive behavior

Lignin-based supercapacitors have received more attention for developing renewable biomass energy storage devices due to multiple pseudocapacitive functional groups in the natural lignin biomolecules and their derivatives. Herein, we confirmed the electrochemical activities of lignin-based composite were greatly boosted by coupling of oxidized kraft lignin (OKL) with hierarchical porous nitrogen-dopped carbon (NC). The synergetic effect between pseudocapacitive groups (mainly hydroquinone group) in OKL and macroporous-mesoporous carbon with interpenetration structure and nitrogen doping was verified by FT-IR, XPS and electrochemical characterizations. The capacitance of OKL/NC composite was achieved 412 Fg(-1) at 1 Ag-1 in an acidic system, which is a twice increase compared to the capacitance (154 Fg(-1)) of NC. (C) 2021 Elsevier Ltd. All rights reserved.