Towards seawater electrolysis in alkaline media: assessing the role of hypochlorite formation
(2026) Journal of the Electrochemical Society — Vol. 173, n° 6, p. 64505 (2026)
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- Authors
Wauthy, Nathan 
- Abstract
- The chlorine ion present in seawater is the most threatening danger to water splitting technologies aiming at directly using the seawater as an electrolyte. In the alkaline route, chlorine can potentially be oxidized to hypochlorite, a toxic and corrosive compound that remains in the electrolyte in aqueous form. However, there is an electrochemical window allowing to completely avoid the formation of hypochlorite. In this work, a set of commercial electrodes and gas separators were tested in a lab-scale electrochemical cell by injecting different concentrations of Cl- in the electrolyte and testing various operating conditions. The latter include varying the imposed current density and KOH concentration in the electrolyte at 70°C. Our results show that the key parameter is the cell voltage, which, if kept under 1.9 V, enables to avoid ClO- formation and its consequences, e.g. corrosion of the electrodes and bipolar plates. With our setup, this condition was successfully met by simultaneously using an electrolyte with at least 30 wt% KOH and limiting the current density to 0.5 A/cm2.
- Affiliations
Citations
Delmelle, R., Wauthy, N., Santoro, R., & Proost, J. (2026). Towards seawater electrolysis in alkaline media: assessing the role of hypochlorite formation. Journal of the Electrochemical Society, 173(6), 64505. https://doi.org/10.1149/1945-7111/ae4ffb (Original work published 2026)