Carbon nanoporous layer for reaction location management and performance enhancement in all-vanadium redox flow batteries

In this study, the performance and reaction location in a VRFB was investigated with a carbon paper electrode that was modified to include a thin layer of multi-walled carbon nanotubes. The nanotube layer was introduced into the electrode at locations on the negative and positive electrode nearest the membrane and nearest the flow field. Results with the nanotube layer on the positive electrode yielded small changes in the performance, despite the location. However, when the nanotube layer was introduced on the negative electrode, the performance was greatly improved when it was closest to the current collector. In this configuration, an 8% increase in power density and a 65 mV increase in cell voltage were observed, compared to a cell with raw carbon paper. This is attributed to the increase in active area of the nanoporous structure in a location where the reaction is favored to occur. Published by Elsevier B.V.