Experimental work was performed to evaluate the Ce3＋/Ce4＋ redox couple in methane sulfonic acid （MSA） electrolyte for use in redox flow battery （RFB） technology. The electrochemical behaviour of the Ce3＋/Ce4＋ in MSA media was investigated using cyclic voltammetry, linear sweep voltammetry, chronoamperometry and rotating disc electrode. The standard rate constant of the Ce3＋/Ce4＋ redox reaction on graphite electrode in MSA was 4.06×10–4 cm/s. The diffusion coefficient of Ce3＋ in MSA was 5.87–6.15×10？6 cm2/s, and was 2.56–2.68×10？6 cm2/s for Ce4＋. The energy efficiency of a cerium-zinc test cell was 74.8%. The high stability of cerium salts in MSA media and relatively fast redox kinetics of the Ce3＋/Ce4＋ redox reaction at graphite ectrode indicated that the Ce3＋/Ce4＋ might be well suited for use in RFB technology.
