Influence of contaminants on PEMFC performance – a multisinglecell approach

• Multisinglecell approach to investigate the effect of BoP contaminants on PEMFC. • Sulfur and fluoroelastomers-based materials are detrimental to cathode Pt catalyst. • Pre-heat treatment of peroxide material gives minimum-to-no contamination effect. • Mass spectrometry reveals low levels of contamination with pre-heat treatment. The impact of materials used in balance of plant (BoP) components of the proton exchange membrane fuel cell (PEMFC) is studied and the effect of the released contaminants on the performance of platinum (Pt) cathode catalyst are evaluated using multisinglecell (MSC) approach as an in-situ electrochemical tool. The effect of contaminants released from ethylene-propylene diene monomer (EPDM) and fluoroelastomers-based (FKM) materials is studied by measuring PEMFC voltage drop as a function of time at different temperatures. Sulfur-cross-linked EPDM and FKM give a drastic poisoning effect with irreversible voltage loss of ∼25 mV and ∼35 mV respectively, without any pre-heat treatment. The pre-heat treatment of these materials significantly reduces the influence of contaminants on the Pt catalyst. Mass spectrometry (MS) analysis further reveals the extent of sulfur-based contaminants (CS 2 ) from sulfur-cross-linked EPDM at temperatures 50 °C – 200 °C. The low concentrations of CS 2 within the operating temperature (<100 °C) of PEMFC can have a strong contamination effect on the Pt catalyst and its recoverability. The results showed that peroxide-cross-linked EPDM is a very promising candidate to replace FKM, which can release perfluoroalkyl substances (PFAS).