A novel Ce4-/Ce3+-V2+/V3+ redox flow cell has been designed. The electrochemical responses of higher concentration Ce4+/Ce3+ couple in H2SO4 solution were investigated via cyclic voltammetry. The normal potential and the kinetic parameters for anodic oxidation of Ce3+ and cathodic reduction of Ce4+ were measured. The results showed the surface of platinum electrode was fully covered with type I oxide that inhibited the reduction of Ce4+. The reversibility of the Ce4+/Ce3+ couple improved with the increase of H2SO4 concentration. Different electrochemically active Substances existed at various state of charge (SOC) and the reversibility of the Ce4+/Ce3+ couple at the carbon electrode was superior to platinum. (C) 2003 Published by Elsevier B.V.