The Performance and Bubble Behavior of an Anion Exchange Membrane Water Electrolyzer under Different Temperatures and Electrolyte Flow Rates

Temperature and flow rate are critical operating parameters that affect the performance and bubble behavior of the anion exchange membrane water electrolyzer (AEMWE), directly influencing mass transfer efficiency and operational stability. To elucidate their underlying mechanisms, an AEMWE with transparent anode end plates was designed to enable in situ observation of bubble dynamics within the anode flow field. By combining electrochemical impedance spectroscopy (EIS) measurement and distribution of relaxation times (DRT) analysis, the performance and bubble characteristics under different temperature–flow rate combinations were systematically investigated. The results indicated that elevating the temperature improved electrolytic performance with minimal impact on bubble coverage. While increasing the flow rate significantly reduced bubble coverage, it concurrently lowered the cell temperature, negatively affecting electrolytic performance. Based on experimental findings, this study reveals the synergistic relationship between temperature and flow rate, offering a physically plausible interpretation that the convective cooling effect at higher flow rates may dominate over the benefits of macroscale bubble removal. It proposes an optimized operational strategy: maintaining the system within an efficient temperature range through coordinated temperature control while keeping flow rate within an appropriate range. This research provides insights for optimizing operating conditions and ensuring efficient, stable operation of AEMWE systems.