Ni electrodes with 3D-ordered surface structures for boosting bubble releasing toward high current density alkaline water splitting

• Published in: Ultrasonics sonochemistry 2023-06, Vol.96, p.106398-106398, Article 106398
• Main Authors: Ma, Jugang, Yang, Mingye, Zhao, Guanlei, Li, Yangyang, Liu, Biao, Dang, Jian, Gu, Junjie, Hu, Song, Yang, Fuyuan, Ouyang, Minggao
• Format: Article
• Language: English
• Subjects: 3D-ordered surface structures; Alkaline water electrolysis; Durability; Gas bubble; High-speed camera; UC and HC intensification
• ISSN: 1350-4177; 1873-2828
• DOI: 10.1016/j.ultsonch.2023.106398

•Ni electrode with 3D-ordered surface structures is constructed by electroetching.•3D-ordered surface structures promote the release of bubbles from the electrode.•High-speed camera confirms that larger bubbles hinder the convection of electrolyte.•The durability of the micro-nano-rough electrode is verified by the accelerated test. The performance of alkaline water electrolysis (AWE) at high current densities is limited by gas bubble generation on the surface of electrodes, which covers active sites and blocks mass transfer, resulting in lower AWE efficiency. Here, we utilize electro-etching to construct Ni electrodes with hydrophilic and aerophobic surfaces to improve the efficiency of AWE. Ni atoms on the Ni surface can be exfoliated orderly along the crystal planes by electro-etching, forming micro-nano-scale rough surfaces with multiple crystal planes exposed. The 3D-ordered surface structures increase the exposure of active sites and promote the removal of bubbles on the surface of the electrode during the AWE process. In addition, experimental results from high-speed camera reveal that rapidly released bubbles can improve the local circulation of electrolyte. Lastly, the accelerated durability test based on practical working condition demonstrates that the 3D-ordered surface structures are robust and durable during the AWE process.