Effect of sulfosalicylic acid on kinetics of Ce3+/Ce4+ electrode reaction

The effect of sulfosalicylic acid (SSA) on the electrochemical behaviour of Ce3+/Ce4+ redox couple was studied using voltammetry at stationary electrode and rotating disc electrode (RDE). When the SSA was added to the Ce3+/Ce4+ electrolyte there was change to the peak current and peak potential, i.e. the increase of peak current and the decrease of peak potential difference. The diffusion coefficient of Ce3+ is 6.5 x 10(-6) cm(2) s(-1) and the standard rate constant of the Ce3+/Ce4+ redox reaction is 3.2 x 10(-4) cm s(-1) the presence of SSA, which are all larger than that in the absence of SSA (3.6 x 10(-6) cm(2) s(-1), 2.0 x 104 cm s(-1)). Therefore, the SSA as the additive in the supporting electrolyte for a cerium redox flow battery (RFB) application will result in a high voltage efficiency and will satisfy an important requirement for a RFB electrolyte.