Ozonated Monolayer Graphene for Extended Performance and Durability in Hydrogen Fuel Cell Electric Vehicles

Hydrogen fuel cells have the potential to revolutionize the heavy-duty transportation sector, but their widespread adoption has been impeded by the limitations of current proton exchange membranes (PEMs). Hydrogen crossover remains a critical challenge, leading to reduced efficiency and accelerated membrane degradation. While previous attempts to incorporate 2D materials into PEMs have shown promise in mitigating crossover, they have unilaterally resulted in compromised proton conductivity and overall performance, caused by mitigation of water permeation through the membrane. [1,2,3]<br/><br/>This work presents a novel and scalable approach to extend both PEM lifetime and performance using UV-ozone treated monolayer graphene as a selective barrier layer without any degradation in performance.<br/><br/>This work utilizes a UV-ozone treatment approach allowing for precise control over the size and density of angstrom and nanometer scale defects in the graphene lattice. By tuning the ozone exposure time, we create a defect distribution that maximizes hydrogen/proton selectivity while minimizing the impact on proton conductivity by facilitating the transport of water. Our results demonstrate a 27% increase in selectivity over state-of-the-art Gore Select membranes, a 24% decrease in hydrogen crossover, and up to a 19% enhancement in current density at 0.7 V. Moreover, our ozonated graphene PEMs exhibit an impressive 39% improvement in durability, displaying no performance loss after a 100-hour accelerated stress test.<br/><br/>The significance of our approach lies in its simplicity and scalability to integrate size selective graphene with traditional PFSA membranes. The UV-ozone treatment is a straightforward post-processing step that can be readily applied to commercially available graphene materials and seamlessly integrated into existing PEM manufacturing processes. This makes our technology a practical solution with immense potential for real-world implementation. This work sets the stage for further advancements in PEM design and opens new avenues for the development of high-performance, ultra-durable fuel cell systems.<br/><br/>[1] S. Kutagulla et al., ACS Appl Mater Interfaces 2023, 15, 51, 59358–59369<br/>[2] M. Komma et al., ACS Appl. Mater. Interfaces 2024, 16, 18, 23220–23232<br/>[3] N.K. Moehring et al., Nanoscale, 2024, 16, 6973