The oxidation of organic additives in the positive vanadium electrolyte and its effect on the performance of vanadium redox flow battery
| Autor: | Nyunt Wai, Adam Whitehead, Günther G. Scherer, Zhichuan J. Xu, Tam D. Nguyen, Moe O. Oo, Arjun Bhattarai, Ghimire P. Chandra |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Renewable Energy
Sustainability and the Environment Chemistry 020209 energy Inorganic chemistry Energy Engineering and Power Technology Vanadium chemistry.chemical_element Sulfuric acid 02 engineering and technology Electrolyte 021001 nanoscience & nanotechnology Ascorbic acid Redox Flow battery chemistry.chemical_compound 0202 electrical engineering electronic engineering information engineering Titration Thermal stability Electrical and Electronic Engineering Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | Journal of Power Sources. 334:94-103 |
| ISSN: | 0378-7753 |
| DOI: | 10.1016/j.jpowsour.2016.10.017 |
| Popis: | Despite many desirable properties, the vanadium redox flow battery is limited, in the maximum operation temperature that can be continuously endured, before precipitation begins in the positive electrolyte. Many additives have been proposed to improve the thermal stability of the charged positive electrolyte. However, we have found that the apparent stability, revealed in laboratory testing, is often simply an artifact of the test method and arises from the oxidation of the additive, with corresponding partial reduction of V(V) to V(IV). This does not improve the stability of the electrolyte in an operating system. Here, we examined the oxidation of some typical organic additives with carboxyl, alcohol, and multi-functional groups, in sulfuric acid solutions containing V(V). The UV–vis measurements and titration results showed that many compounds reduced the state-of-charge (SOC) of vanadium electrolyte, for example, by 27.8, 88.5, and 81.9% with the addition of 1%wt of EDTA disodium salt, pyrogallol, and ascorbic acid, respectively. The cell cycling also indicated the effect of organic additives on the cell performance, with significant reduction in the usable charge capacity. In addition, a standard screening method for thermally stable additives was introduced, to quickly screen suitable additives for the positive vanadium electrolyte. |
| Databáze: | OpenAIRE |
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