Novel anti-corrosion anodes facilitate stable seawater electrolysis

Prof. Lu Zhiyi, Prof. Chen Liang and coworkers at the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences, have developed a novel anti-corrosion anode via chemical fixation of sulfate, achieving stable seawater electrolysis for more than 10,000 hours. The study is published in Advanced Materials.

Hydrogen can be generated through seawater electrolysis and provides renewable energy sources, which helps preserve freshwater supplies and thus has been considered a cost-effective sustainable energy conversion and storage strategy. However, highly concentrated Cl^– in seawater triggers severe anode corrosion, limiting the application and commercialization of on-site seawater electrolysis for hydrogen production.

Scientists at NIMTE doped Ba²⁺ into NiFe-LDH (NF-LDH) catalysts to synthesize NiFeBa-LDH (NFB-LDH) catalysts through a facile one-step hydrothermal method.

The NFB-LDH catalyst chemically fixed free SO₄²⁻ by atomically dispersed Ba²⁺ and preferentially absorbed SO₄²⁻ on the electrode surface. This formed a dense SO₄²⁻ layer to repel Cl^–, thus protecting the anode from corrosion.

The NFB-LDH achieved unprecedented stability for more than 10,000 hours at a constant current density of 400 mA cm⁻² in both alkaline seawater and alkaline saline electrolytes.

Compared with commercial Ni anodes, NFB-LDH anodes showed superior stability and activity under simulated industrial conditions.

This work may shed light on the commercialization of seawater electrolysis technology and relevant anti-corrosion electrode design.