Enhancing Lithium-Ion Battery Performance with Ni1−xFexS-Biocarbon Composites: Improving Cycle Stability and Rate Capability through Multilayered Biocarbon Nanosheet Formation and Fe Doping

Given the growing demand for high-performance, stable, eco-friendly, and cheap lithium-ion batteries (LIBs), the development of affordable and environmentally friendly high-performance anode materials for LIBs has garnered considerable attention. Herein, to address this need, NiS (known for its high theoretical capacity) was grown on a porous biocarbon (BC) matrix to afford a highly conductive LIB anode material capable of accommodating the charge/discharge-induced volume changes and thus ensuring cycle stability. The cycling performance of this material (NiS–BC) was further enhanced by doping with Fe. The best-performing (Ni_0.8Fe_0.2S–BC) anode demonstrated an initial discharge capacity of 1,374.4 mAh g⁻¹ at 0.5 A g⁻¹, which further increased to 1,796.4 mAh g⁻¹ after 100 cycles, and the origins of this high performance were probed by instrumental analysis. The results contribute to the development of next-generation LIBs for applications requiring high capacity, high output, and long-term cycle stability, such as electronic devices, electric vehicles, and energy storage systems. Moreover, the use of BC aligns with a prominent trend in modern battery research, namely, the development of secondary batteries simultaneously exhibiting high performance and sustainability.