Electrospun Carbon Nanofibers as Alternative Electrode Materials for Vanadium Redox Flow Batteries

Non-woven carbon nanofiber networks were produced by electrospinning. Electrospinning is a process that can easily be up-scaled, producing carbon fibers that can be used as electrodes with increased surface area and reaction sites. The structure of electrospun carbon nanofibers (ES-CNFs) was investigated by scanning electron microscopy and compared to a commercial carbon felt (CF). The electrochemical properties of the obtained ES-CNFs were studied for the negative half-cell reaction in a three-electrode setup and a single-cell battery test system. The performance and stability of the generated materials were tested by charging and discharging the cell and carrying out X-ray diffraction and Raman spectroscopy before and after operation. An increase in the energy efficiency of about 10 % was achieved when using five sheets of free-standing ES-CNFs compared to commercial CFs, revealing the potential use of ES-CNFs as electrode materials in the negative half-cell of all-vanadium redox flow batteries.