Dual Zn/Zr Hybrid Framework‐Integrated Membranes With Enhanced Proton Conductivity and Durability for High‐Temperature <scp>PEM</scp> Fuel Cells

ABSTRACT This study proposes an innovative strategy for fabricating advanced composite membranes based on a poly[2,2′‐(m‐phenylene)‐5,5′‐bibenzimidazole] (PBI) matrix for high‐temperature proton exchange membrane fuel cells (HT‐PEMFCs). A co‐synthesized hybrid porous framework incorporating both Zn‐ and Zr‐based nanostructures was integrated into the PBI backbone, ensuring uniform dispersion and strong interfacial bonding, as verified by comprehensive structural and morphological characterizations. This dual‐framework architecture promoted the formation of continuous proton‐conductive channels and enhanced membrane stability under demanding operating conditions. Furthermore, the membranes were utilized after acid doping, and the hybrid structure effectively mitigated the acid leaching issue, ensuring stable long‐term proton conductivity. At 0.6 V and 170°C, the membranes achieved a current density of ≈630 mA/cm 2 , demonstrating the critical role of structural optimization in improving fuel cell efficiency. These findings offer valuable insights into designing scalable, durable, and thermally stable membranes for next‐generation HT‐PEMFC applications.