Electrochemical properties of electrolyte for lead fluoroborate redox flow battery prepared with recovered lead

The electrochemical properties of electrolyte for soluble lead flow battery(SLFB) are a key factor for the improvement of its performance. Pb(BF₄)₂ in which Pb²⁺ ions are highly soluble is cheaper and more stable than conventional Pb(CH₃SO₃)₂. This paper presents the electrochemical properties of HBF₄ and Pb(BF₄)₂ prepared with recovered lead for the electrolytes of SLFB. The density difference of reagent grade and recovered lead electrolytes is less than 0.05 g/cm³ and their viscosities increase up to 132 %, 120 %, respectively when concentration of Pb(BF₄)₂ changes from zero to 2.0 mol·dm⁻³. The conductivity of 1.5 mol·dm⁻³ electrolyte prepared with recovered lead has a peak when concentration of HBF₄ is less than 1.0 mol·dm⁻³. The results of cyclic voltammetry, linear sweep voltammetry and constant current charge/discharge test showed that impurities of recovered lead exert insignificant influences on the Pb²⁺/Pb and Pb²⁺/PbO₂ reactions. These results are promising to apply recovered lead to SLFB.