“…In vanadium redox flow battery (VRFB) research, stationary 1 linear sweep voltammetry (S-LSV) and stationary cyclic voltammetry (S-CV) are the most prevalent techniques used for the fast assessment of the kinetic performance of surface-modified carbon felt electrodes, and numerous studies have been published on that topic (Flox et al, 2013a,b;Gao et al, 2013;Hammer et al, 2014;Suárez et al, 2014;Liu et al, 2015;Park and Kim, 2015;He et al, 2016He et al, , 2018Kim et al, 2016;Park et al, 2016;Ryu et al, 2016;Zhang et al, 2016;González et al, 2017;Jiang et al, 2017;Ghimire et al, 2018;Xiang and Daoud, 2019;Yang et al, 2019). However, regarding the complex diffusion domain inside a felt electrode, the common approach of relating the peak-to-peak separation of an S-CV curve to the electrodes' kinetics (valid for a planar electrode in semi-infinite diffusion space only; Matsuda and Ayabe, 1954;Nicholson and Shain, 1964;Nicholson, 1965) does not seem to be appropriate.…”