Novel Nitrogen‐Doped Porous Carbon with High Surface Areas Prepared from Industrial Alkali Lignin for Supercapacitors

Abstract As a waste of the pulp and papermaking industry, industrial alkali lignin (IAL) was employed to prepare nitrogen‐doped porous carbon by pre‐carbonizing of lignin under a N 2 atmosphere at 400 °C and carbonizing with the assistance of urea at 800 °C for 1 h. The porosity and surface chemical properties of the obtained porous carbons strongly depended on the alkaline environment of the lignin. The obtained porous carbons showed specific surface areas ranging from 1.759 m 2 g −1 to 1482 m 2 g −1 and nitrogen contents of 1.12 % to 7.78 %. The unique microstructure and nitrogen functionalities endowed the porous carbon with a high capacitance of 283.4 F g −1 in 6 mol L −1 KOH aqueous electrolytes. In addition, the optimal porous carbon exhibited excellent rate capability (212.0 F g −1 at 20 A g −1 ) and cycle durability (97.6 % after 10000 charge‐discharge cycles), making it a promising electrode material for supercapacitors.