Graphite felt with vapor grown carbon fibers as electrodes for vanadium redox flow batteries

Several methods to produce vapor grown carbon fibers (VGCFs) on graphite felt as electrodes for vanadium redox flow batteries (VRB) were described. The experiments include graphite felt preparation and VGCF production onto graphite fiber in the felt. Several attempts were made using nickel and cobalt catalyst coatings on the graphite felt. The nickel catalyst came from nickel nitride solution. It was prepared by dipping graphite felt into the solution and decomposed using heat treatment. Cobalt nanoparticles were sprayed onto graphite felt. Both experiments resulted in carbon nanotubes and VGCFs growth onto graphite fiber in the felt. The experimental results show that VGCFs and carbon nanotubes with the range of 20 to 70 nm in diameter are grown in the graphite felt using different catalysts. The encouraged results show the single VRB cell test with new electrodes can increase the charge/discharge efficiency by more than 12% compared to conventional graphite felt.