Electrospinning fabrication of ethanol lignin/polyacrylonitrile composite carbon fibers for supercapacitor applications.

Supercapacitors, known for their high safety, long cycle life, rapid charging and discharging rates, and high power density, are widely used in portable electronic devices, aerospace applications, and new energy electric vehicles. However, the high cost and environmental impact of polyacrylonitrile (PAN)-based carbon fibers, the most commonly used electrode materials, limit their further development. In this study, low molecular weight ethanol lignin was mixed with PAN for the first time, and lignin-based carbon fibers with excellent electrochemical properties were prepared using electrospinning technology. The study investigated precursor solutions with different lignin-to-PAN ratios to optimize electrochemical performance. The prepared nanofibers and carbon fibers were systematically characterized using thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and electrochemical analysis. The results indicate that when the lignin-to-PAN mass ratio is 2:1, the resulting carbon fibers exhibit the best electrochemical performance, with a specific capacitance of 173.64 F g-1 at a current density of 0.5 A g-1, significantly higher than that of pure PAN carbon fibers. This research provides substantial evidence for the use of biomass-based lignin as a sustainable alternative to PAN in carbon fiber production and opens new possibilities for the application of lignin-based carbon fibers in energy storage, particularly in supercapacitors.