Projects per year
Abstract
Bifunctional air electrodes with tuned composition consisting of two precious metal-free oxide catalysts are manufactured for application in rechargeable zinc-air flow batteries and electrochemically tested via long-term pulse charge and discharge cycling experiments at 50 mA cm−2 (mean). NiCo2O4 spinel, synthesized via direct impregnation on carbon nanofibers or nickel powder and characterized by energy dispersive X-ray spectroscopy and X-ray diffraction experiments, shows high activity toward oxygen evolution reaction with low charge potentials of < 2.0 V vs. Zn/Zn2+. La0.6Sr0.4Co0.2Fe0.8O3 perovskite exhibits bifunctional activity and outperforms the NiCo2O4 spinel in long-term stability tenfold. By combining the catalysts in one bi-catalyzed bifunctional air electrode, stable performances of more than 1000 h and 450 cycles are achieved when supplied with oxygen and over 650 h and 300 cycles when supplied with synthetic air. In addition, the pulse charging method, which is beneficial for compact zinc deposition, is successfully tested on air electrodes during long-term operation. The oxygen evolution potentials during pulse, i.e. at tripled charge current density of 150 mA cm−2, are only 0.06–0.08 V higher compared to constant charging current densities. Scanning electron microscopy confirms that mechanical degradation caused by bubble formation during oxygen evolution results in slowly decreasing discharge potentials.
Original language | English |
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Article number | 251 |
Pages (from-to) | 488 - 497 |
Journal | Electrochimica Acta |
DOIs | |
Publication status | Published - 2017 |
Projects
- 1 Finished
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LUZIFLOW - Zinc/air redox flow battery with new electrolytes for the storage of regenerative energy and the net stabilisation
Hacker, V., Pichler, B. E., Gollas, B. & Taucher-Mautner, W.
1/04/15 → 30/09/18
Project: Research project