Abstract

This study investigates the feasibility of operating a laboratory-scale electrolysis cell with synthetic seawater and evaluates whether the integrated bipolar plates and sealing components can withstand saline electrolysis conditions. A single-cell system with a nominal active area of 100cm² was assembled and operated using synthetic seawater based on NaCl solutions. Systematic experiments examined the influence of temperature, salt concentration and KOH addition on current-voltage behaviour. The test system included automated data acquisition and control, and selected components were examined after operation by post-mortem inspection. The experiments demonstrated that synthetic seawater electrolysis is technically feasible and that the bipolar plate and sealing concept remained functional throughout the laboratory test campaign without documented leakage-related or mechanical failure. Increasing temperature and NaCl concentration increased current density, while very small KOH additions produced only limited improvements. More strongly alkaline conditions resulted in significantly better electrochemical performance. At the same time, chlorine formation and corrosion limited the practical operating window, and post-mortem analysis revealed pronounced deposits particularly on the oxygen side of the cell. Overall, the results are encouraging and demonstrate a suitable component platform for further development. Future work should focus on corrosion-resistant bipolar plate coatings, optimization of the anodic side, longer-term durability testing and evaluation under more realistic seawater compositions.

Keywords: Seawater electrolysis; Electrolysis stack; Measurements under temperature and seawater content