Kinetics of Oxygen Evolution Reaction in Soluble Lead Flow Batteries

Kinetics of oxygen evolution reaction (OER) on PbO 2 deposited glassy carbon disk electrode in methanesulfonic acid (MSA) is analyzed with cyclic voltammetry and electrochemical impedance spectroscopy for soluble lead flow battery applications. The effect of concentration of the active species (Pb 2+ ) and the electrolyte (MSA) on the OER at the deposited PbO 2 layer is investigated. The apparent activation energy of the OER on PbO 2 , deposited at various overpotentials, is obtained from the Arrhenius and Eyring analyses. The apparent activation energy follows a unique trend that it increases with overpotential, reaches a maximum and decreases thereafter. This is consistent with the PbO 2 specifically deposited from MSA of low concentrations (<1 M), where the gel layer composed of hydrated PbO(OH) 2 is also found. It is observed that low MSA concentration is preferred for limiting the OER at the positive electrode.