Coordinated Multi‐Component Gradient Engineering of Catalyst Layers for Advanced Polymer Electrolyte Fuel Cells

Abstract Membrane electrode assemblies (MEAs) are critical to emerging energy technologies such as polymer electrolyte fuel cells (PEFCs), but their performance is often limited by challenges in reactant transport, ionic conduction and water management within the catalyst layer (CL). Conventional CL architectures, whether uniform or layered, struggle to manage these competing transport phenomena effectively, leading to mass transport losses, poor proton conduction and structural inconsistencies. To address these limitations, this study presents a continuous linear gradient CL design that breaks from traditional approaches. By employing a precision‐controlled dual‐nozzle spray coating technique, a smooth gradient in Pt/C ratio, ionomer content and ionomer type is fabricated across the CL thickness. Uniquely, this method relies exclusively on commercially available materials, strategically positioned where they are most effective. The resulting architecture aligns with natural electrochemical gradients in the CL, facilitating improved reactant accessibility, proton transport and water handling. This structure not only enhances performance under realistic operating conditions but also improves long‐term durability. Furthermore, by selectively placing materials only where needed, it has the potential to reduce overall material usage and cost. This gradient approach offers a scalable and practical path toward next‐generation, high‐efficiency PEFCs.