Comparison of Electrospun Carbon−Carbon Composite and Commercial Felt for Their Activity and Electrolyte Utilization in Vanadium Redox Flow Batteries

A low cost highly active carbon−carbon composite fiber felt was produced by electrospinning a mixture of polyacrylonitrile and carbon black powder using poly acrylic acid as a binder for high carbon black loading. The newly designed high‐surface area electrode material showed promising results for use as electrode material for both the negative and positive half‐cell of vanadium redox flow batteries. Battery test results demonstrated promising performance for the electrospun carbon fibers at current densities below 60 mA cm−2, but were less active at higher values. The microstructure of the felt was characterized by X‐ray computed tomography to obtain the porous pathways, which facilitate electrolyte transport. The obtained results will help us to understand the role of porosity in the performance of the battery and to consequently improve the design of the carbon‐filled electrospun material. Go with the flow: A highly loaded carbon−carbon composite fiber felt electrode is fabricated by electrospinning. The felt is tested as an electrode material in an all‐vanadium redox flow battery and shows promising results. The microstructure of the felt is characterized by using X‐ray computed tomography to obtain the porous pathways.