Spatial-Confinement-Driven Bubble Self-Management for Compact, High-Performance Water Electrolyzers

Advancements in renewable energy have accelerated the development of water electrolysis technologies as a direct avenue for sustainable hydrogen. Conventional electrolyzers, however, suffer substantial efficiency losses because of bubble accumulation during operation, necessitating complex auxiliary modules and parasitic energy inputs. In this study, we pioneer a spatial confinement strategy that utilizes buoyancy-driven bubble transport for self-sustaining hydrodynamic management, significantly simplifying system architecture and reducing energy demands. Using in situ techniques like particle image velocimetry and high-speed imaging, we demonstrate how spatial constraints induce fluid recirculation, enhance mass transfer, and minimize bubble buildup. The optimized prototype achieves a 2-fold increase in current density and reduces the reactor volume by over 50%, highlighting its potential for scalable applications. This physics-driven design principle offers a new paradigm for next-generation energy storage and conversion engineering across a broad spectrum of gas-involved electrochemical systems.