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

• Hierarchical porous structure and heteroatomic doping of carbon substrates were designed. • The synergy of hierarchical porous structure with mesoporous and macroporous interpenetrating were studied. • The heteroatom and hydroquinone groups greatly improves the pseudocapacitive of the composite. 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 F g −1 at 1 A g −1 in an acidic system, which is a twice increase compared to the capacitance (154 F g −1 ) of NC. .