Lignin-Derived Nitrogen-Doped Carbon/SiO x Nanocomposites for Applications for Lithium Storage

To address the limitations of conventional graphite- and Si-based anodes, a facile in situ synthesis strategy was developed to construct lignin-derived nitrogen-doped porous carbon/SiOx (NLPC/SiOx) nanocomposites using sodium lignosulfonate as a renewable precursor. The influence of SiOx content on structural characteristics and lithium storage performance was systematically investigated. Structural analyses revealed that nanoscale SiOx particles were uniformly dispersed within the porous N-doped carbon framework, establishing intimate interfacial contact. This integrated architecture facilitates electron and Li+ transport while accommodating volume variations during repeated lithiation/delithiation. The optimized NLPC/SiOx-25 electrode delivered a reversible capacity of 879 mAh g−1 at 0.1 A g−1, with 89.3% capacity retention after 100 cycles. Furthermore, it maintained a capacity of 260 mAh g−1 after 4000 cycles at 5 A g−1, demonstrating excellent long-term cycling stability. The enhanced electrochemical performance is attributed to the synergistic effects of nanoscale SiOx dispersion, the conductive N-doped carbon framework, and improved interfacial integration. This work presents a sustainable strategy for developing durable Si-based anodes while promoting the high-value utilization of lignin-derived industrial byproducts.