Superhydrophobic Stainless Steel Bipolar Plates with Fractal Structure for Fuel Cells by Nanosecond Laser Ablation

Abstract

Bipolar plate (BP) is one of the crucial components in proton exchange membrane fuel cells (PEMFCs). In extreme cold weather, massive vapor condensation happens right at vehicle start‐ups, which likely causes “water flooding” and thus shortens the lifespan of PEMFCs. Herein, a superhydrophobic stainless steel bipolar plate (SH‐SS BP) that is fabricated by nanosecond laser ablation is reported. Through a repeated low‐energy processing strategy, fractal surface microstructure is fabricated, which has not been reported for SS BP. By grafting stearic acid (SA) monolayer, a robust SH‐SS BP is obtained with a contact angle of 151.74°. The fractal microstructure greatly enhances the contact area between SH‐SS BP and membrane electrode assembly (MEA), which improves interfacial contact resistance (ICR: 9.816 mΩ cm2 at 1.5 MPa). The SH‐SS BP shows significantly enhanced anticorrosion performance (= A cm−2) by effectively reducing penetration of corrosive. The ability of improving water management in PEMFC under extreme cold condition is further demonstrated in a simulated PEMFC. This study opens new opportunity to reinforce metallic BPs by a simple, low‐cost, and robust route, which is valuable in improving comprehensive weather fastness of PEMFC.