Polarization Characteristics of an Alkaline Water Electrolyzer Under Marine Sloshing Conditions

Marine hydrogen production systems deployed on ships and floating platforms are inevitably subjected to complex multi-degree-of-freedom motions induced by waves and wind, which may influence electrolyzer performance. However, experimental investigations under realistic marine motion conditions remain limited. In this study, a laboratory-scale alkaline water electrolyzer was installed on a six-degree-of-freedom (6-DOF) motion platform to experimentally investigate the influence of marine sloshing on polarization characteristics. The experimental design focuses on the fluctuation of cell polarization behavior under dynamic conditions using a single-cell configuration. Typical single-degree-of-freedom (SDOF) and coupled multi-degree-of-freedom (MDOF) motions were reproduced to simulate representative marine operating environments. The results show that sloshing motion leads to a moderate increase in cell voltage compared with static conditions. Under SDOF conditions, the voltage increase remains within 7%, with sway and roll identified as the dominant disturbance modes. Under coupled MDOF conditions, the voltage increase is further amplified but remains below 10.2% even under 6-DOF motion. The results also reveal that the effect of coupled motions is nonlinearly weaker than the linear superposition of individual motions. This study provides experimental evidence that alkaline electrolyzers can maintain stable operation under realistic marine dynamic conditions. These deviations correspond to limited efficiency losses and remain within typical engineering tolerances, suggesting that marine motion has a manageable impact on electrolyzer performance and offers practical guidance for offshore system design and control.