Fe/Ni-Catalyzed Pyrolysis of Sugarcane Bagasse Lignin to Graphitized Porous Carbon for Lithium-Ion Battery Anodes

Developing sustainable electrode materials from renewable biomass is important for improving the environmental sustainability of lithium-ion batteries (LIBs). Sugarcane bagasse lignin, an abundant agricultural byproduct, is a promising precursor for lignin-derived carbon anode materials, yet systematic comparative studies on catalyst-dependent structure evolution and LIB performance remain limited. In this study, lignin extracted from sugarcane bagasse by an ethanosolv process was converted into Fe- and Ni-catalyzed lignin-derived carbon materials via catalytic pyrolysis at 900 °C. The effects of catalyst type, metal-to-lignin ratio, and pyrolysis holding time on textural properties, structural features, and electrochemical behavior were systematically investigated. Among the studied conditions, the Fe-catalyzed sample prepared at a metal-to-lignin ratio of 1:2.5 and a holding time of 3 h (GLKL-2.5Fe-3h) exhibited the highest BET surface area (332.71 m2 g−1) and the most developed porous morphology. SEM, TEM, Raman, and XRD analyses indicated catalyst-dependent differences in pore development, carbon domain morphology, and local graphitic ordering, with Fe- and Ni-catalyzed samples following distinct structural evolution pathways. Electrochemical testing showed that GLKL-2.5Fe-3h delivered the highest initial discharge capacity (759 mAh g−1), retained 165 mAh g−1 after 500 cycles, and exhibited more favorable rate performance and lower apparent interfacial resistance than the other tested samples under the same conditions. In contrast, the Ni-catalyzed and solvothermally treated samples showed lower capacity retention and/or less favorable electrochemical behavior. These results demonstrate the strong effect of catalyst type on the structure-performance relationship of bagasse lignin-derived carbon anodes and support Fe-catalyzed lignin-derived carbon as a promising sustainable anode candidate for LIB applications.