Electrochemical modification of a pyrolytic graphite sheet for improved negative electrode performance in the vanadium redox flow battery

Electrocatalysis at Electrodes for Vanadium Redox Flow Batteries

“…In case of supercapacitor electrode studies, repetitive electrode potential cycling resulted in swelling of the topmost part of, for example glassy carbon, associated with significantly enlarged values of C DL [319,320]. The negative VRFB electrode reaction was remarkably accelerated at pyrolytic graphite by electrochemical treatment in 1 M H 2 SO 4 at E Ag/AgCl = 2.1 V for one minute [321]. Oxygen surface groups were verified by infrared spectroscopy.…”

Detrimental role of hydrogen evolution and its temperature-dependent impact on the performance of vanadium redox flow batteries

“…Taylor et al [17] also questioned the stability of the activation treatment on an oxidised glassy carbon electrode and reported low stability of the surface oxygen groups over cycling measurements. This degradation is usually associated with the negative side reaction and therefore it is considered as the rate determining reaction in the cell [18] . The undesired reaction of hydrogen evolution associated with the negative side reaction has been investigated by many researchers.…”

High-power nitrided TiO2 carbon felt as the negative electrode for all-vanadium redox flow batteries

“…Moreover, it is known that after the mild oxidation of the carbon felt at 500ºC for 5 h. the cell energy efficiency is improved, which is attributed to the formation of oxygen related functional groups [39]. The appropriate formation of C-OH, C=O, and C-O functionalities increases the standard heterogeneous electron transfer rate for V 3+ /V 2+ , from 3.2x 10 -7 to 1 x 10 -3 cm s -1 , one of the highest values found in the literature [40]. These electrode modifications help to decrease the fraction of the current directed towards H2 evolution in the same way as reported in our previous paper on TiO2:H graphite felt [29].…”