High capacity surface route discharge at the potassium-O2 electrode

Chen, Yuhui; Jovanov, Zarko P.; Gao, Xiangwen; Liu, Jingyuan; Holc, Conrad; Johnson, Lee R.; Bruce, Peter G.

Abstract

Discharge by a surface route at the cathode of an aprotic metal-O2 battery typically results in surface passivation by the non-conducting oxide product. This leads to low capacity and early cell death. Here we investigate the cathode discharge reaction in the potassium-O2 battery and demonstrate that discharge by a surface route is not limited to growth of thin (<10 nm) metal oxide layers. Electrochemical analysis and in situ Raman confirmed that the product of the cathode reaction is a combination of KO2 and K2O2, depending on the applied potential. Use of the low donor number solvent, acetonitrile, allows us to directly probe the surface route. Rotating ring-disk electrode, electrochemical quartz crystal microbalance and scanning electron microscope characterisations clearly demonstrate the formation of a thick > 1 μm product layer, far in excess of that possible in the related lithium-O2 battery. These results demonstrate a high-capacity surface route in a metal-O2 battery for the first time and the insights revealed here have significant implications for the design of the K-O2 battery.

Citation

Chen, Y., Jovanov, Z. P., Gao, X., Liu, J., Holc, C., Johnson, L. R., & Bruce, P. G. (2018). High capacity surface route discharge at the potassium-O2 electrode. Journal of Electroanalytical Chemistry, 819, 542-546. https://doi.org/10.1016/j.jelechem.2018.03.041

• Journal Article Type: Article
• Acceptance Date: Mar 20, 2018
• Online Publication Date: Mar 21, 2018
• Publication Date: 2018-06
• Deposit Date: Mar 27, 2018
• Publicly Available Date: Mar 27, 2018
• Journal: Journal of Electroanalytical Chemistry
• Print ISSN: 1572-6657
• Electronic ISSN: 1873-2569
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 819
• Pages: 542-546
• DOI: https://doi.org/10.1016/j.jelechem.2018.03.041
• Keywords: Metal-air; Oxygen reduction
• Public URL: https://nottingham-repository.worktribe.com/output/938367
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S1572665718302108
• Contract Date: Mar 27, 2018