The catalyst layers in high-temperature polymer electrolyte membrane fuel cells (HT-PEMFC) were composed of Pt/C, polymer binder, and phosphoric acid (H3PO4). Understanding the detailed distribution of PTFE binder with H3PO4 on Pt/C surface can help design higher cell performance and durability of HT-PEMFCs. In this study, we used a molecular dynamics simulation to investigate the detailed molecular distribution of PTFE-binder, whose content ranges from 7.7 to 35.1wt% and H3PO4 on Pt/C surface in catalyst layers at room (298.15K) and operating (433.15K) temperatures. Pair correlation function (PCF) and surface coverage analysis shows that the distribution of H3PO4 on the Pt particle meaningfully decreased when the PTFE-binders' contents increased over 20.0wt% at 298.15K. However, the H3PO4 can more contact on the Pt surface at 433.15K because H3PO4 can permeate into the PTFE-binder due to higher mobility of H3PO4 than 298.15K. In the case of distribution of H3PO4 on the carbon surface, the intensities of PCF and surface coverage were meaningfully decreased with increasing PTFE-binder levels up to ~20.0wt% because PTFE-binder fully covered the carbon surface up to ~20.0wt% at 298.15 and 433.15K.

Investigation on the distribution of H3PO4 and PTFE binder on catalyst layer of high-temperature polymer electrolyte membrane fuel cells: Molecular dynamics simulation approach

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.