Investigation of the relationship between oxygen bubble behaviour and local thermal stress in PEMWE

Abstract

Understanding the interplay between gas bubble evolution and thermal behaviour is vital to improving the efficiency and durability of Proton Exchange Membrane Water Electrolysers (PEMWEs). This study presents a real-time visualisation approach that combines synchronised microscopy and infrared thermal mapping to analyse anodic gas bubble formation and its thermal impact at varying current densities. Results show a strong correlation between localised bubble dynamics, nucleation, growth, and coalescence and non-uniform temperature distributions. Regions with intense bubble evolution exhibit elevated thermal signatures driven by local electrochemical heat generation and bubble-induced thermal insulation. At higher current densities, intensified coalescence increases bubble accumulation, impeding convective heat transfer and creating persistent thermal hotspots. These hotspots coincide with heightened electrochemical activity and may indicate early-stage material stress and degradation. These findings highlight the value of real-time diagnostics and provide critical insights for optimising electrode design, improving thermal management, and informing predictive models.