Polyethylene Glycol Functionalized Alumina-Based Composite Membrane with High-performance for Alkaline Water Electrolysis

Abstract

Green hydrogen is currently the dominant trend in the evolution of hydrogen energy, producing almost no greenhouse gas emissions. Alkaline water electrolysis (AWE) is recognized as a leading and well-established technology for producing green hydrogen. However, safety hazards may occur during hydrogen production currently as defective commercial separate membranes used in the AWE process. Therefore, it is imperative to create a membrane characterized by low area resistance, high stability, and high bubble point pressure (BPP) to realize high-performance AWE. Herein, we synthesize alumina-based composite membranes with Y₂O₃-added and polyethylene glycol functionalized Al₂O₃ for AWE through a phase inversion method. The porous composite membrane exhibits excellent hydrophilicity, with a lower contact angle of approximately 55°. It also presents exceptional performance metrics, including a low area resistance of about 0.17 Ω cm², an ultra-high BBP of approximately 4.4 bar, and excellent mechanical properties with a tensile strength of around 25 MPa. The membranes achieved a current density of up to 2.5 A cm^-2 under 2.0 V voltage in a 30 wt% KOH solution at 80 °C by utilizing commercial catalysts. Notably, the composite membranes exhibited remarkable stability, maintaining operation for over 1200 hours at a 2.0 A cm^-2 current density without any performance degradation at 80°C. Furthermore, this composite membrane possesses outstanding gas-barrier capability with H₂ and O₂ purity higher than 98.70% and 99.69%, respectively. The above results demonstrate that the prepared novel high-performance alumina-based composite membrane for hydrogen generation has significant potential for applications within the AWE process.