Improving interfacial contact with patterned cross-linked membrane constructed by hot-pressing for high-temperature proton exchange membrane fuel cells

The interfacial adhesion between the proton exchange membrane (PEM) and catalyst layers (CLs) is a critical determinant of power density in high-temperature proton exchange membrane fuel cells (HT-PEMFCs). Although ordered three-dimensional patterning has been demonstrated to enhance PEM/CL interfacial properties in low-temperature PEMFCs, its effective implementation in HT-PEMFCs remains challenging due to stringent thermal-mechanical stability requirements under harsh operating conditions; existing studies often lack integrated solutions for simultaneous interfacial and bulk membrane optimization. A synergistic strategy is developed herein that concurrently establishes an ordered 3D interfacial architecture and induces in-situ cross-linking of the PEM via a facile one-step hot-pressing process. This engineered interface not only substantially enlarges the electrochemically active contact area but also minimizes interfacial resistance, while the cross-linked network confers exceptional mechanical robustness and thermal stability. Consequently, the patterned membrane achieves a 133 % enhancement in electrochemical active surface area (ECSA) and delivers a peak power density of 1062.7 mW cm −2 , representing a significant advancement over unpatterned membranes and previously reported HT-PEMFC systems. This work establishes a new design paradigm for PEMs, wherein interfacial engineering and bulk membrane stabilization are holistically integrated to enable high-performance, durable HT-PEMFCs.