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Electrochemical Behavior of the Ce4+ / Ce3+ Couple in the Novel Ce- V Redox Flow Cell
Published online by Cambridge University Press: 15 March 2011
Abstract
A novel Ce4+/Ce3+- V2+/V3+ redox flow cell has been investigated. It was composed of the Ce4+/Ce3+ couple, which replaced the V5+/V4+ couple of the all6vanadium redox flow cell, and the V2+/V3+ couple. The normal potential and the kinetic parameters for anodic oxidation of Ce3+ and cathodic reduction of Ce4+ were measured. The results showed that 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, but both higher energy efficiency and coulombic efficiency were observed in 0.5 mol/dm3 H2SO4 solution. Different electrochemically active substances were found to exist at various state of charge (SOC) and the reversibility of the Ce4+/Ce3+ couple at the carbon electrode was found to be superior to platinum electrode. Periodic charge6discharge measurements were conducted under constant current and constant load with the proposed Ce6V redox flow cell. The results indicated that the coulombic efficiency remained around 90% and the discharge voltage stabilized between 1.5 and 1.2 V. But as the cycle numbers increased, the discharge capacity declined a bit and a better result might be expected by improving the separator materials and increase the concentration of electro6active materials. By comparison with the existing Fe6Cr, Fe6Ti and all6vanadium redox flow cell, the Ce6V system has a higher open6circuit voltage (OCV). And results from this preliminary study suggest that the novel Ce6V redox flow cell is a promising energy storage system and is worthy of further studies.
- Type
- Research Article
- Information
- MRS Online Proceedings Library (OPL) , Volume 1127: Symposium T – Mobile Energy , 2008 , 1127-T01-03
- Copyright
- Copyright © Materials Research Society 2009