(166e) Advances in PEFC Short-Stack Diagnostics: Understanding MEA Durability Enhancements for Heavy Duty Fuel Cell Applications

The transportation sector currently accounts for a large portion of global greenhouse gas and particulate emissions, contributing to many adverse effects. Decarbonization efforts will rely on the rapid development and deployment of electric vehicles to replace existing fleets. Hydrogen fuel cells have received considerable interest as a cleaner replacement for diesel engines for long distance transportation. To outcompete diesel engines, fuel cell systems must operate with high fuel efficiency and durability to lower the total cost of ownership to a competitive level. With these ambitious targets, we need to rapidly integrate promising materials in membrane electrode assemblies (MEAs) to assess and improve their performance and durability.

The development of high-performance and durable MEAs is challenging due to the difficultly of optimizing many interrelated processing and fabrication variables (e.g. ink formulation and mixing, deposition method, solvent ratio, hot-pressing, conditioning, etc) that can significantly impact overall performance and durability. Unfortunately, this process is highly empirical and therefore requires substantial time and resources when incorporating a novel component. There’s a clear need to accelerate the ability to assess MEA durability and identify key design parameters to advance the development of hydrogen fuel cell technology.

To address the limitations in testing capacity, we utilize short stacks to rapidly screen MEAs up to 10 times faster than single cell testing. We have developed several testing protocols for short stacks that approximate the potential cycling in catalyst, membrane, and MEA accelerated stress tests. The performance losses of individual cells can be monitored throughout testing in rainbow-stack and repeat MEA configurations. Levering our experience in electrochemical diagnostics development, we have recently developed galvanostatic techniques to monitor critical MEA properties (like hydrogen crossover, electrochemical surface area, and ohmic resistance) of individual cells in the stack. Coupling electrochemical characterization with high throughput performance screening, our aim is to fast-track the discovery of structure-performance relationships essential to durable fuel cell development. This presentation will highlight these new diagnostic capabilities and our recent results evaluating advanced MEAs developed within the Million Mile Fuel Cell Truck consortium.