Laser-induced graphene as the microporous layer in proton exchange membrane fuel cells

[Display omitted] •Cost-effective and rapid laser manufacturing method of graphene-based MPLs.•Tandem surface patterning by laser contouring for controlling hydrophobicity.•PTFE binder-free, all-graphene MPLs overcoming water management issues.•Improved performance due to high conductivity, porosity, and water elimination.•Tailored material properties and chemical composition, high scalability. Porous nanocarbons have been established as materials of choice in the manufacturing of microporous layers (MPLs) for proton-exchange membrane fuel cells (PEM FCs). However, obtaining mechanically and chemically stable materials at competitive yield-to-cost ratios still remains a critical objective, with pyrolytic techniques having shown great promise for bulk material production. A recent advancement in the field, the acclaimed laser-induced graphene (LIG) method employs low-cost industrial engravers for the laser pyrolysis of polymeric substrates into graphene-based foams with distinctive 3D porous networks. In this work, we apply the LIG method on polyimide precursors to obtain surface-patterned hydrophobic graphene foams, and we develop a low-temperature decal method (LTD-LIG) for the direct transfer of non-sacrificial platinum-coated LIG on Nafion® membranes to serve as the MPL in PEM FCs. Obtained by a readily scalable and inexpensive manufacturing method, the assembled LIG-based FC prototype overcomes the water management and mechanical stability problems typically encountered by graphene-based MPLs to present impeccable fuel crossover and power performance at 888.33 mW cm−2 mg−1 of anodic Pt load at 80 °C and 80% RH, delivering a 20% increase in power density compared to a reference FC bearing a commercial carbon black MPL assembled with the same loadings.