Production and Characterization of Electrospun Carbon Nanofibers as Cathode Support for Sodium-Ion Cells

The present work deals with the production of carbon nanofibers (CNF) via electrospinning, a low-cost and scalable manufacturing technique yielding fibers with diameter down to few nanometers. Starting from a polymeric solution, fibers are spun and collected in thick layers (mat) having random orientation. This texture allows to have structures with high interconnected porosity. Polymeric fibers are then thermally treated to obtain CNF via pyrolisis. The obtained carbon mats are successively used as conductive and porous supports for cathodes of a Sodium-Ion cell. Such CNF support brings two main advantages compared to battery electrodes produced with standard manufacturing techniques: the high porosity allows the liquid electrolyte to diffuse throughout the entire thickness of the cathode, exploiting the whole amount of electroactive material loaded into the electrode; it offers an excellent electronic conductive path to drain electrons upon redox reaction thus lowering the internal resistive loss. Understanding of electrospinning and otpimization of the setup is a major achievements. Results concerning the optimization of the process flow are reported. After fabrication, morphological, structural and compositional characterizations are carried out on CNF mats of different thickness.