A study on Pb2+/Pb electrodes for soluble lead redox flow cells prepared with methanesulfonic acid and recycled lead

Abstract

Electrodeposition and electrodissolution reactions of the Pb 2? /Pb electrode were studied on a glassy carbon rotating disk electrode in aqueous solutions of CH 3 SO 3 H and Pb(CH 3 SO 3 ) 2 . The electrolytic parameters, kinematic viscosity and ionic conductivity, were determined with various concentrations of CH 3 SO 3 H and Pb(CH 3 SO 3 ) 2 . The diffusion coefficient of Pb 2? in this electrolyte prepared with CH 3 SO 3 H was determined by the Levich Equation. Both the concentrations of CH 3 SO 3 H and Pb(CH 3 SO 3 ) 2 were found responsible for the equilibrium potential shifts and exchange current density variations. The electrochemical processes at the Pb 2? / Pb electrode were identified as being under mixed ohmicdiffusion control. The electrolyte conductivity and the ionic activity of Pb 2? were recognized as important parameters for designing the soluble lead redox flow cells. During constant current charge-discharge measurement, the specific capacity of the Pb 2? /Pb electrode was about 253 mAh g -1 Pb, about 98 % of the theoretical value. The impurity elements Fe, Ba, Al, and Zn in the Pb 2? electrolytes prepared with recycled lead exhibited insignificant influences on the Pb 2? /Pb reactions. It is reasonable to believe that the recycled lead can be applied in soluble lead redox flow batteries, and the cost may be further reduced with recycled lead because expensive impurity-control processes seemed to be avoidable. Graphical AbstractKeywords Soluble lead redox flow cells Á Redox flow battery Á Methanesulfonic acid Á Lead electrodeposition Á Lead acid battery Á Recycled lead