Detrimental role of hydrogen evolution and its temperature-dependent impact on the performance of vanadium redox flow batteries
By Fetyan, Abdulmonem; El-Nagar, Gumaa A.; Lauermann, Iver; Schnucklake, Maike; Schneider, Jonathan; Roth, Christina
Published in Journal of Energy Chemistry
2018
Abstract
This paper addresses the damaging role of the parasitic hydrogen evolution reaction (HER) in the negative half-cell of a vanadium redox flow battery (VRFB) on state-of-the-art carbon felt electrodes at different temperatures. It was found that increasing the temperature resulted in a better catalytic performance for both the positive and negative half-cell reactions. In addition, increasing the temperature significantly enhanced the undesired HER at the negative side. Operating the VRFB cell at higher temperature led to a decrease in the coulombic efficiency attributed to the higher hydrogen production. More pronounced hydrogen production caused an oxidation on the surface of the carbon fibers and a degradation of the electrode as indicated from scanning electron microscopy and X-ray photoelectron spectroscopy measurements. This observed degradation results in fading of the overall performance of the vanadium redox flow battery over time.