Fuel cell stack redesign and component integration radically increase power density

Summary

The drawbacks of conventional channel-rib flow fields and gas diffusion layers (GDLs) significantly limit the mass transfer and water management capability of proton exchange membrane fuel cells (PEMFCs), impacting volumetric power density. We report a GDL-less design of electrode-flow field integration comprised of graphene-coated Ni foam and ultrathin (9.1 μm) carbon nanofiber film as an alternative to conventional channel-rib flow fields and GDLs, which substantially reduces membrane electrode assembly volume (90%), reactant transport distance (96%), and concentration impedance (88.6%), resulting in a remarkable 50% power density increase. The GDL-less design provides an effective strategy for the rational design of integrated electrode-flow field and will guide the future development of PEMFCs for their practical applications in energy conversion technologies. We estimate that the peak volumetric power density a PEMFC stack employing GDL-less design can achieve is 9.8 kW L⁻¹, representing an increase of more than 80% compared with the state-of-the-art commercial PEMFC stack.