• • Seawater contains ~0.5 M Cl− ions, which at high current densities can oxidize to chlorine or hypochlorite, competing with the oxygen evolution reaction (OER) and reducing Faraday efficiency while corroding the electrolytic cell.
• • The review systematically categorizes chloride suppression strategies into three areas: directional catalyst design for OER, electrolyte composition optimization, and electrolytic cell engineering, each targeting the mitigation of chlorine-induced side reactions.
• • Industrial-scale SWE requires addressing both efficiency and durability; the review emphasizes that without effective chloride suppression, the lifespan of electrolytic cells is curtailed, hindering commercialization.
• • The review highlights that future development must focus on integrating these strategies to achieve stable, high-efficiency seawater electrolysis, with the goal of meeting projected hydrogen demand of at least 148 million tons annually by 2050.