Bulk hydrophobic gas diffusion layer with interpenetrating network for high-performance fuel cells.

[Display omitted] • GDL with excellent bulk hydrophobicity and strength based on interspersed PP network. • Novel bulk- and self- hydrophobicity GDL require no fluoride posttreatment. • Excellent water management under high current density in PEMFC operation. • Cost-effective production of high-performance GDL through paper making. In the quest for sustainable energy, proton exchange membrane fuel cells (PEMFCs) are emerging as a key technology due to their high efficiency and low pollutant emissions. However, the performance and longevity of PEMFCs rely heavily on effective water management within the gas diffusion layer (GDL). Traditional GDLs, comprised of carbon fiber paper treated with perfluorinated hydrophobic agents, suffered from environmental, economic, and performance limitations and exhibited unsatisfactory water regulation due to the surface hydrophobicity. To overcome these challenges, we have developed a fluorine-free bulk hydrophobic GDL with an interpenetrating network composed of graphene, cellulose fiber, and modified polypropylene fiber with impressive mechanical strength (22 MPa) and enhanced hydrophobicity without the use of harmful fluorinated agents through the scalable papermaking. The resulting GDL offers significantly improved PEMFC performance by enhancing water management, achieving a current density of 1.25 A cm−2 at 0.6 V and a maximum power density of 0.746 W cm−2. Furthermore, it exhibits superior water management capabilities compared to commercial GDL under high current density and demonstrates a more straightforward, less energy-intensive production process. Our findings suggest a scalable, cost-effective pathway for advanced GDL manufacturing, promoting a shift towards more sustainable and high-performing PEMFCs. [ABSTRACT FROM AUTHOR]