The effect of Co2+ on positive deposits with the assistance of tartaric acid additive in soluble lead flow batteries

The positive deposit layer is passivated to seriously affect the service life of soluble lead flow batteries . Based on the oxidation reaction of high valence Cobalt ions in the electrocatalytic OER process, Pb 2+ can be oxidized to form Pb 4+ that reduces the formation of the passivation layer. The hydroxyl radical adsorbed by Co 3/4+ is disaffiliated from the active site. It is conducive to the formation of lead dioxide . In this work, a dense and flat sedimentary layer is obtained on the carbon fiber by adding 5 mmol·L −1 of Co 2+ . The tartaric acid with a delocalized structure is used to improve the conductivity and reduce the impedance of the sediment layer. As a result, the average coulomb efficiency of the flow cell reaches 97.8 %, and its average energy efficiency is 80.9 % in 100 cycles. It would provide a theoretical basis for improving the cycle life of soluble lead flow batteries .