Preparation of hierarchical-pore gas diffusion layer for fuel cell

Proton exchange membrane fuel cell (PEMFC) is a promising automotive power source that has been gradually applied due to its many advantages such as pollution-free and low-temperature start-up. The gas diffusion layer (GDL) is a key component for water and gas management in PEMFC. It can directly affect the performance of PEMFC. In this paper, we prepared a new type of GDL with hierarchical pores to improve the performance of PEMFC at high current density. The new GDL mainly includes a commercial carbon paper layer and two microporous layers on the same side of carbon paper. The microporous layer near carbon paper was modified with pore former, and another layer was produced without pore former. The pore size of the middle microporous layer was controlled by the content of pore former and times of sonication. From the results of the polarization curve, electrochemical impedance spectroscopy, water contact angle, conductivity, and pore size distribution, it was found that GDL with hierarchical pores shows obvious advancement than commercial GDL. The PEMFC performance was tested to compare the new and commercial GDL. The results show that the peak power of our GDL at 100% humidity reaches 1.24 W/cm(2) and the limit current density is 3.500 A/cm(2). The modification of the pore size of the microporous layer near the carbon paper side can improve the water management ability of the fuel cell.