Impact of surface oxygen functionalization on local oxygen transport resistance at the fuel cell cathode

Abstract

The high oxygen transport resistance at the carbon/ionomer interface is one of the primary limitations for proton exchange membrane fuel cells (PEMFCs) with low platinum (Pt) loadings. This study uses molecular dynamics (MD) simulations to explore how oxygen-containing functional groups on carbon supports influence ionomer distribution and oxygen permeation. Results show that C=O and C-O-C groups prevent the dense overlay of ionomer backbones, enhancing phase segregation and improving both oxygen diffusion and solubility. By optimizing surface oxygen species and ratios (4 %–8%), these groups significantly reduce local oxygen transport resistance (R_Local). This work offers new insights for designing modified carbon supports to improve PEMFC performance by enhancing oxygen permeation and reducing R_Local.