Investigation of electrolytes of the vanadium redox flow battery (VII): Prediction of the viscosity of mixed electrolyte solution (VOSO4 + H2SO4 + H2O) based on Eyring's theory

Highlights: • Viscosity and density for aqueous VOSO₄ + H₂SO₄ system was determined. • The viscosity coefficients – B_i and Δμ_i^≠0 were estimated. • A predicting function of the viscosity for mixed electrolyte. -- Abstract: Viscosities of ternary mixtures of VOSO₄ + H₂SO₄ with water were measured across the entire range of total ionic strength (I_T = 1 to 11) mol·kg⁻¹ and over a temperature range of (283.15–318.15) K. The viscosity B-coefficients of the binary aqueous were determined from Jones-Dole equation. Using the B-coefficients, the activation parameters for viscous flow of the solutes were further evaluated. On the basis of Eyring's equation, a semi-empirical method to estimate the viscosity for concentrated and mixed electrolyte solutions was put forward. The estimated viscosity values of VOSO₄ + H₂SO₄ + H₂O are in quite good agreement with the corresponding experimental results with the average absolute relative deviation of 0.96%.