Membrane-shaped MOF proton conductors

Escalating global energy demand has spurred intensive research into alternative energy technologies, among which proton-exchange membrane fuel cells (PEMFCs) stand out for their high efficiency and environmental benignity. However, conventional proton conductors like Nafion® face critical limitations, including water-dependent conductivity, high production costs, and poor performance under high-temperature/low-humidity conditions. Metal–organic frameworks (MOFs), with their tunable structures, high porosity, and diverse functionalization, have emerged as promising candidates to overcome these challenges. This review systematically summarizes recent progress in membrane-shaped MOF proton conductors, focusing on three mainstream fabrication strategies: MOF–polymer blend membranes, MOF glass membranes, and substrate-deposited MOF films. The proton conduction mechanisms, structural design principles, and performance optimization strategies for each type are discussed. Additionally, the current challenges and future perspectives in advancing MOF-based membranes for practical PEMFC applications are highlighted.