The synthesis of porous carbons from a lignin-rich residue for high-performance supercapacitors

Fabricating electrically conductive porous electrode for supercapacitors from abundant raw materials remains a significant challenge in the field of energy storage. 3D porous carbon with high surface areas was synthesized by high-temperature carbonization and activation of lignin from cornstalks. When used as electrode materials in supercapacitors they showed a specific capacitance of 280 F g⁻¹ and an area-specific capacitance of 1.3 F cm⁻² at a current density of 0.5 A g⁻¹. An assembled symmetric supercapacitor showed a high energy density of 7.7 Wh kg⁻¹ at power density of 5 200 W kg⁻¹. It is demonstrated here that the use of lignin waste to fabricate electrode materials is feasible, affording lignin new value-added utilization.