High Performance Interpenetrating Network Type Proton Exchange Membranes for PEM Water Electrolysis

Abstract This study reports the development of a cost‐effective, interpenetrating network‐based proton exchange membrane (IPN‐PEM) with high stability, durability, and effective performance for proton exchange membrane water electrolysis (PEMWE). Structural analysis is carried out using FT‐IR and XPS, analysis confirming the successful formation of an interpenetrating network of polyethylene, styrene, and divinylbenzene with sulfonic acid (SO ₃ H) groups. Under the PEMWE conditions, the IPN‐PEM‐50 membrane of thickness 50 µm achieved a current density of 1000 mA cm ⁻² at 2.1 V at 80 °C. The stability analysis of the electrolyser is also carried out which maintains a stable voltage of 1.83 V at 500 mA cm ⁻² over 100 h and a stable voltage of 2.08 V at 800 mA cm ⁻² over 29 h. In seawater electrolysis mimicking system, the IPN‐PEM‐50 MEA demonstrated good performance, reaching a current density of ≈400 mA cm ⁻² at 2.1 V highlighting its potential for seawater electrolysis. The IPN‐PEM displays its mechanical stability with a tensile strength of 11 MPa, a Young's modulus of 80 MPa, with the thermal stability >200 °C. Cost‐effectiveness, durability, and stability of IPN‐PEM make a promising alternative to the high‐cost and degradation‐prone PFSA membranes.