Highly anti-corrosive NiFe LDHs–NiFe alloy hybrid enables long-term stable alkaline seawater electrolysis

• Published in: Rare metals 2024, Vol.43 (9), p.4321-4332
• Main Authors: Li, Jia-Hong, Chen, Hao, You, Si-Hang, Yang, Gan-Xin, Liu, Peng, Gao, Meng-Qi, Chen, Shu-Guang, Zhang, Fei-Fei
• Format: Article
• Language: English
• Subjects: Amorphous alloys; Biomaterials; Chemistry and Materials Science; Contaminants; Corrosion; Corrosion effects; Electrodes; Electrolysis; Energy; Hydrogen evolution reactions; Hydrogen fuels; Intermetallic compounds; Iron compounds; Materials Engineering; Materials Science; Metal foams; Metallic Materials; Nanoscale Science and Technology; Nickel base alloys; Nickel compounds; Original Article; Oxygen evolution reactions; Physical Chemistry; Seawater; Substrates
• ISSN: 1001-0521; 1867-7185
• DOI: 10.1007/s12598-024-02780-z

Owing to the significant potential of alkaline seawater electrolysis for converting surplus power into eco-friendly hydrogen fuel, we developed bifunctional electrodes that integrate low-crystalline NiFe LDHs and amorphous NiFe alloy on a Ni foam (NF) substrate to enhance this process. Driven by the battery-like characteristics of NiFe LDHs, an anti-corrosive and active outer layer of NiFe vac OOH continuously forms over time in the hybrid on the anode for the oxygen evolution reaction (OER), effectively mitigating powder shedding caused by corrosion induced by multiple anions in seawater. Meanwhile, the strong bond between the hybrid and the NF substrate maintains intact hybrid coatings to ensure a relatively high overall conductivity of the electrodes, significantly reducing the negative effects of structural degradation during the OER and hydrogen evolution reaction (HER), as well as the accumulation of contaminants on the electrode surfaces. In long-term tests, these bifunctional hybrid electrodes maintained stable performance, even at a high current density of 500 mA·cm −2 . The cell voltage increased by only 88 mV over 1000 h to 1.970 V during saline electrolysis and by 103 mV over 500 h to 2.062 V during seawater electrolysis. Hence, this study provides valuable insights into efficient and stable seawater electrolysis using NiFe LDHs–NiFe alloy hybrids. Graphical abstract