Atomic layer deposition in proton exchange membrane fuel cells: precision control from catalysts to membrane electrode assemblies

Abstract

Proton exchange membrane fuel cells (PEMFCs) are pivotal for a hydrogen-based economy, yet their commercialization is impeded by high costs and poor long-term durability. These challenges stem from the reliance on expensive platinum-group metal (PGM) catalysts and degradation of the membrane electrode assembly (MEA). Atomic Layer Deposition (ALD), a vapor-phase technique with atomic-level precision and unparalleled conformality, is a powerful strategy for designing functional materials and interfaces. ALD enables a paradigm shift from simple material modification to the atomic-scale engineering of the full MEA. This review highlights ALD's transformative impact across PEMFCs. For catalysts, we detail the synthesis of core–shell nanostructures and protective overlayers that maximize PGM utilization and mitigate degradation. For other components, we explore how conformal ALD films on membranes and gas diffusion layers (GDLs) enhance proton conductivity and optimize water management. We also discuss advances in scalable ALD reactor technologies. Finally, we identify key challenges and opportunities for realizing high performance, durable PEMFCs through atomic-scale design.