IMMORTAL will develop exceptionally durable and high power density MEAs well beyond the current state of the art up to TRL4 by building on understanding of fuel cell degradation pathways specific to heavy-duty truck operation and developing lifetime prediction models from extensive real-life stack operation, accelerated stress test and load profile cycles on short stacks. IMMORTAL encompasses OEMs, tier 1 suppliers, and leading industrial and academic/research organisation partners with long expertise in fuel cell science and technology. Building on best developments from the FCHJU, the project will not only develop significantly more durable MEAs that will be transferable to other fields, but will accelerate competitiveness of the European fuel cell truck sector by providing recommendations at system level to improve durability, and designs that contribute to increasing stack power density and to reducing the PEMFC system cost. Accordingly, the specific objectives of the project are to: Develop new materials concepts for world-leading components (electrocatalysts, membranes) by building mitigation strategies to fuel cell operation-induced degradation into their design to ensure both their activity and their stability, and improve the interfaces between them to minimise resistances; Realise the potential of these components in MEAs by introducing novel electrode and MEA constructions to deliver a step-change in durability while exceeding 1.2 W/cm2 at 0.675 V; Develop load profile tests for heavy-duty MEA performance and durability assessment, including input from real-life usage profiles from H2Haul; Validate the MEA performance and durability in full size cell short stacks using extended load profile testing and achieve a predicted lifetime of 30,000 hours.