Concerning the stability of seawater electrolysis: a corrosion mechanism study of halide on Ni-based anode

Sixie Zhang; Yunan Wang; Shuyu Li; Zhongfeng Wang; Haocheng Chen; Li Yi; Xu Chen; Qihao Yang; Wenwen Xu; Aiying Wang; Zhiyi Lu

doi:10.1038/s41467-023-40563-9

Concerning the stability of seawater electrolysis: a corrosion mechanism study of halide on Ni-based anode

Nat Commun. 2023 Aug 10;14(1):4822. doi: 10.1038/s41467-023-40563-9.

Authors

Sixie Zhang^#^{1

2

3}, Yunan Wang^#^{1

2

3}, Shuyu Li^{3

4}, Zhongfeng Wang^{1

2

3}, Haocheng Chen^{1

2}, Li Yi^{1

2}, Xu Chen^{1

2}, Qihao Yang^{1

2}, Wenwen Xu^{5

6}, Aiying Wang^{3

4}, Zhiyi Lu^{7

8

9}

Affiliations

¹ Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, Zhejiang, P. R. China.
² Qianwan institute of CNITECH, Ningbo, 315201, Zhejiang, P. R. China.
³ University of Chinese Academy of Sciences, Beijing, 100049, P. R. China.
⁴ Key Laboratory of Marine Materials and Related Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, Zhejiang, P. R. China.
⁵ Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, Zhejiang, P. R. China. xuwenwen@nimte.ac.cn.
⁶ Qianwan institute of CNITECH, Ningbo, 315201, Zhejiang, P. R. China. xuwenwen@nimte.ac.cn.
⁷ Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of Zhejiang Province, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, Zhejiang, P. R. China. luzhiyi@nimte.ac.cn.
⁸ Qianwan institute of CNITECH, Ningbo, 315201, Zhejiang, P. R. China. luzhiyi@nimte.ac.cn.
⁹ University of Chinese Academy of Sciences, Beijing, 100049, P. R. China. luzhiyi@nimte.ac.cn.

^# Contributed equally.

Abstract

The corrosive anions (e.g., Cl^-) have been recognized as the origins to cause severe corrosion of anode during seawater electrolysis, while in experiments it is found that natural seawater (~0.41 M Cl^-) is usually more corrosive than simulated seawater (~0.5 M Cl^-). Here we elucidate that besides Cl^-, Br^- in seawater is even more harmful to Ni-based anodes because of the inferior corrosion resistance and faster corrosion kinetics in bromide than in chloride. Experimental and simulated results reveal that Cl^- corrodes locally to form narrow-deep pits while Br^- etches extensively to generate shallow-wide pits, which can be attributed to the fast diffusion kinetics of Cl^- and the lower reaction energy of Br^- in the passivation layer. Additionally, for the Ni-based electrodes with catalysts (e.g., NiFe-LDH) loading on the surface, Br^- causes extensive spalling of the catalyst layer, resulting in rapid performance degradation. This work clearly points out that, in addition to anti-Cl^- corrosion, designing anti-Br^- corrosion anodes is even more crucial for future application of seawater electrolysis.