A New Integrated GDL with Wavy Channel and Tunneled Rib for High Power Density PEMFC at Low Back Pressure and Wide Humidity

Abstract Proton exchange membrane fuel cells (PEMFCs) have garnered significant attention due to their high efficiency and low emissions. However, PEMFC always suffers mass transfer and water management in performance improvement. Herein, an integrated gas diffusion layer (GDL) with wavy channel and micro‐tunneled rib is designed and prepared to achieve faster and gentler mass transfer and excellent water management capability by laser engraving. Outstandingly, the new integrated GDL can use the back pressure of air as low as 0 and 50 kPa to respectively achieve 80% and 90% of fuel cell performance realized under pure oxygen. Such high performance is mainly due to the turbulent flow caused by wavy channel and express removing pathway of liquid water provided by micro‐tunneled rib. Moreover, the new integrated GDL also shows wide humidity tolerance from 40% to 100% and a very high specific volume power density of 16,300 W L−1 due to the thin thickness of new integrated GDL. This new integrated GDL is expected to be widely used in PEMFC and other energy conversion devices.