The effects of side chain (SC) length of perfluorosulfonic acid (PFSA) polymers on the structure of PEM fuel cell catalyst layer (CL) have been studied using molecular dynamics simulation. Two possible transport paths of reactant molecules towards platinum (Pt) surface are inferred based on the visualization of CL configurations. And the sandwich-like structure of CL is observed. Moreover, the results show that the short PFSA SCs will lead to the high accessibility of sulfonate acid groups, water molecules and hydronium ions to Pt particles, which can improve the transport of protons to Pt particles. Additionally, this paper has also found that PFSA SC length has little effect on the migration of hydronium ions.
Keywords PEM fuel cell; Catalyst layer; Structure; Side chain length; Molecular dynamics simulation