Heteroatom-doped porous carbon microspheres derived from ionic liquid-lignin solution for high performance supercapacitors

In this work, nitrogen and phosphorus dual-doped alkali lignin-based carbon microspheres (MLCM) were prepared by pre-oxidation and carbonization of ionic liquid ([Mmim]DMP)-lignin solution and used as green-based supercapacitor electrode materials. Compared with the directly carbonized alkali lignin carbon (LC), MLCM had a spherical structure with higher specific surface area (938.1 m(2)/g) and pore volume (0.64 cm(3)/g). Moreover, MLCM materials showed superior electrochemical performance. In the 1 mol/L H2SO4 electrolyte system, MLCM presented the highest specific capacitance of 338.2F/g at a current density of 0.8 A/g. Furthermore, MLCM was used as a positive and negative electrode material to assemble a symmetrical supercapacitor. The resultant device maintained excellent cycle stability after 5000 times of charging and discharging process at 2 A/g. Overall, the facile, green and sustainable synthesis strategy of heteroatom-doped porous carbon microspheres developed in this work opens a new avenue for the fabrication of high-performance carbon electrode materials, especially based on abundant and renewable lignin. (C) 2022 Elsevier Inc. All rights reserved.

Automated summary

In this study, nitrogen and phosphorus dual-doped carbon microspheres were prepared using a facile and sustainable method. The microspheres exhibited a spherical structure with high specific surface area and pore volume, and showed superior electrochemical performance. Additionally, the microspheres were successfully applied as electrode materials in a supercapacitor, demonstrating excellent cycle stability.