Sustainable PAN–lignin/CoFe2O4 composite nanofibers as high-performance anode materials for lithium-ion batteries: synthesis, characterization, and electrochemical evaluation
摘要
This study presents the development of sustainable composite electrodes combining polyacrylonitrile (PAN)–lignin carbon nanofibers with cobalt ferrite (CoFe2O4) nanoparticles for advanced lithium-ion battery anodes. The composite materials were fabricated via centrifugal spinning followed by controlled carbonization at 800 °C under argon atmosphere. Comprehensive characterization using X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy (FTIR) confirmed the formation of amorphous carbon structures with localized graphitic ordering and well-crystallized CoFe2O4 spinel phase. The carbonized fibers exhibited uniform morphology (582 nm–1.09 μm diameter) with interconnected porous structures favorable for electrochemical applications. Electrochemical performance was systematically evaluated for composite electrodes containing 0%, 25%, 50%, and 75% CoFe2O4 loadings through galvanostatic charge–discharge testing, cyclic voltammetry, and electrochemical impedance spectroscopy. The optimal composition (25% CoFe2O4) demonstrated exceptional performance with an initial discharge capacity of 800 mAh g−1 at 0.05 A g−1, maintaining 250 mAh g−1 after 6 cycles. At higher current density (0.5 A g−1), this electrode delivered 400–450 mAh g−1 initially and retained 100 mAh g−1 after 50 cycles, significantly outperforming pure PAN–lignin electrodes (100–150 mAh g−1 initial, degrading to 25 mAh g−1). The superior performance stems from synergistic effects between the lignin-derived carbon matrix providing structural stability and the electrochemically active CoFe2O4 enhancing lithium storage capacity through conversion reactions. This work successfully demonstrates an environmentally sustainable, high-performance anode material that addresses critical limitations of conventional graphite electrodes while maintaining competitive electrochemical characteristics for practical lithium-ion battery applications.