Lignin-derived hierarchical porous carbon prepared using cellulose nanofibrils as templates for high-performance supercapacitors

The development of sustainable electrode materials is essential for advancing energy storage technologies. Biomass-derived porous carbons, particularly those from lignin, have garnered significant interest due to their renewability and tunable structures. However, controlling the micropore/mesopore proportion of the biomass-derived porous carbons is still challenging. Herein, a high-performance hierarchical porous carbon was synthesized by utilizing hydrolysate lignin as carbon precursor, cellulose nanofibrils (CNF) as mesopore templates, and KOH as activator. During the carbonization of lignin, the CNF templates promoted the formation of mesopores (≈20 nm), while KOH activation produced micropores and smaller mesopores (≈4 nm). A series of lignin-derived carbon materials were prepared by adjusting the amount of CNF and KOH, and an optimized carbon electrode with a specific capacitance of 228.6 F g -1 was achieved at a current density of 0.5 A g -1 . Furthermore, the symmetric supercapacitors (SCs) assembled from the lignin-derived carbon possessed a high energy density of 9.68 Wh·kg -1 and a capacitance retention rate over 93% after 10,000 cycles. The CNF templating strategy facilitated the preparation of hierarchical porous carbon materials from lignin and promoted their high-value utilization in high-performance supercapacitors. ● Raw biomass like lignin was chose as carbon precursor. ● Mesoporous channels are built by cellulose nanofibrils templates. ● CLK 100 C 10 had a high SSA (1316.7 m 2 g -1 ) and capacitance (228.6 F g -1 ). ● The SCs with CLK 100 C 10 electrode retains 93.3% capacity after 10,000 cycles. ● The SCs successfully powers an LED light and a calculator.