One-step synthesis of lignin-derived carbon nanofibers without the need for stabilization: Characterization and applications

Abstract

Thermal oxidative stabilization is a crucial parameter in carbon nanofiber (CNF) synthesis which which is important for the retention of fiber geometry during the rigorous carbonization process. However, its conventional implementation is burdened by significant time and energy expenditures. This study explores the feasibility of circumventing the stabilization step and its repercussions on the properties of lignin-PVA-derived electrospun CNF mats. Electrospun mats were subjected to carbonization after thermal stabilization (St-CNF) and without thermal stabilization (NSt-CNF). The morphological analysis revealed that despite the exclusion of stabilization, the fibrous structure remains intact without fusion. However, its noticeable impact on carbon yield, graphitic content, and defect density of CNF has been observed. In comparison to NSt-CNF, the St-CNF has higher carbon yield and mass loss fraction, suggesting additional cross-linking and thermal stability. Additionally, a higher specific surface area (381.5 m²/g) and pore volume (0.40 cc/g) were also observed in St-CNF compared to NSt-CNF (162.9 m²/g, 0.15 cc/g), enhancing the electrochemical properties such as specific capacitance (191.5 F/g), energy and power density (26.6 Wh/kg at 520.5 W/kg) of St-CNF. This study provides valuable insight into the properties of lignin-based CNFs, prepared by including or excluding the stabilization step, and explores their potential effect in energy storage applications.