期刊
CHEMICAL ENGINEERING JOURNAL
卷 427, 期 -, 页码 -出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.cej.2021.130862
关键词
Rechargeable Zn-air batteries; Bubble behaviors; Oxygen evolution reaction; Carbon corrosion
资金
- Anhui Provincial Natural Science Foundation [2008085ME155]
- USTC Research Funds of the Double First-Class Initiative [YD2090002006]
- CAS Pioneer Hundred Talents Program [KJ2090130001]
- USTC [ES2090130110, KY2090000065]
- Yanchang Petroleum [ES2090130110]
- RGC Collaborative Research Fund (CRF) from Research Grant Council, University Grants Committee, Hong Kong SAR [C5031-20G]
- Guangdong Provincial Education Department Special Project of Key Research Areas [2020ZDZX2066]
An in-depth investigation into gas evolution on the air electrode during charging process of Zn-air batteries reveals that bubble formation significantly affects electrochemical performance. Increasing catalyst loading leads to smaller and sparser bubbles on the electrode surface, improving stability during charging. At low current densities, self-cleaning of the electrode from bubbles is ideal for efficient charge.
Although tremendous efforts are made in developing stable Zn electrodes and bifunctional catalysts in rechargeable Zn-air batteries, the charging process is few reported. Herein, an in-depth investigation into the gas evolution on the air electrode is conducted by in-situ characterization. It is found that the charging process can be divided into three stages: no obvious bubbles, small bubbles owing to the oxygen evolution, and large bubbles owing to oxygen evolution and carbon corrosion. The post analyses illustrate that the severe bubble formation can deteriorate the electrochemical performance of the air electrode. With the catalyst loading increases, the bubbles on the surface become smaller and sparser. At low current densities, the air electrode can keep selfclean from bubbles, which is the ideal state for the charge. Whereas with an increase of the current density, the large-bubble stage is enlarged, and more bubbles are attached to the surface, leading to extra charge impedance. As the extent of discharge/charge reduces, the three stages disappear, and only small bubbles can be found on the surface, which is favourable for the stable operation. This work provides a profound understanding of the charging behaviors on the air electrode, facilitating the development of high-performance Zn-air and other metal-air batteries.
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