Aramid Nanofiber-Modified Phenolic Resin Enhances Electrochemical Carbon Corrosion Resistance of Carbon Paper for Proton Exchange Membrane Fuel Cells

The low mechanical strength and limited stability of the phenolic resin (PF)-based carbon matrix in carbon paper (CP) significantly compromise the operational reliability of proton exchange membrane fuel cells (PEMFCs). To address this, aramid nanofibers (ANF) are introduced to modify the PF, aiming to simultaneously enhance the mechanical performance and electrochemical corrosion resistance of CP. The results demonstrate that ANF-modified CP achieves a ∼70% reduction in in-plane resistivity alongside increases in tensile and flexural strengths by 104.58% and 121%, respectively. Electrochemical characterization further reveals that the ANF-modified CP exhibits a higher corrosion potential ( E corr ) of 0.503 V and a lower corrosion current density ( I corr ) of 0.240 μA·cm –2, indicating significantly improved corrosion resistance. Performance evaluations in PEMFCs show that CP impregnated with ANF-modified PF maintains enhanced structural integrity and interfacial adhesion. Under 1.4 V cyclic operating conditions, while the limiting current densities and limiting power densities of the ANF-modified CP decreased (from 1.385 A·cm –2 and 0.374 W·cm –2 to 1.013 A·cm –2 and 0.273 W·cm –2, respectively), high power output was still sustained. This study presents, for the first time, the incorporation of aramid nanofibers into phenolic resin-modified CP to construct a highly conductive and corrosion-resistant carbon framework with a three-dimensional cross-linked architecture. This strategy offers a novel approach to the design of gas diffusion layers in proton exchange membrane fuel cells. Furthermore, it holds significant potential for extension to the optimization of interfaces involving nonprecious metal catalyst layers and microporous layers, thereby enhancing the durability and power density of fuel cells.