Nitrogen-doped lignin-derived porous carbons for supercapacitors: Effect of nanoporous structure

Lignin-derived carbon electrode materials for supercapacitors can be prepared from industrial lignin with a high carbon content and a rich benzene ring structure. However, the capacitive performance is significantly affected by the nanoporous structure of the lignin-derived carbon. In this study, three nitrogen-doped nanoporous carbons were prepared using alkali lignin as a carbon source to examine the effect of different nanopore distributions on the electrochemical performance. Carbon activated by ZnC2O4 (PLC-Zn) had a hierarchical porous structure composed of nanosheets, endowing it with a combined ability to store charge and transfer ions. The specific capacitance of PLC-Zn reached a maximum of 254F/g at 0.5 A/g, surpassing that obtained by the microporous-dominated carbon activated by K2CO3 (PLC-K) and mesoporous-dominated carbon obtained by SiO2 template method (PLC-Si). This study provides theoretical guidance for the preparation of excellent lignin-derived carbon electrode materials.