Easily accessible 3D flow fields through 3D-patterned GDL to enhance PEMFC performance via excellent water–gas separation transport

Abstract

Proton exchange membrane fuel cells (PEMFCs) are considered highly efficient energy conversion devices utilizing sustainable green energy. However, commonly occurring water flooding and inefficient mass transfer at high current densities significantly restrict the advancement of higher power density due to obstructed electrochemical reactions. Herein, we developed a readily available three-dimensional (3D) flow field by assembling a regularly 3D-patterned gas diffusion layer (GDL) with a conventional bipolar plate to overcome these challenges. The 3D-patterned GDL with ribs and channels was prepared by multi-step vacuum filtration using a specialized mold. The channels in the 3D-patterned GDL provided independent shortcuts for water drainage, while the channels in the conventional bipolar plate offered independent pathways for air, facilitating clear separation between water and gas transport. Consequently, the 3D flow field effectively prevented water flooding and demonstrated exceptional humidity tolerance under varying air supply conditions. Moreover, it exhibited a lower pressure drop and achieved a high peak power density of 1.7 W cm⁻². Under a low air stoichiometric ratio of 1.5, it showed a 73% improvement in performance compared to the conventional flow field, with only a 5% fluctuation under wide humidity conditions. Given its easy availability, the new 3D flow field, combining a 3D-patterned GDL with a conventional bipolar plate, presents an unprecedented concept in 3D flow field design and demonstrates considerable potential for the development of ultra-high-performance fuel cells.