Effects of Ozone on the Performance of a Polymer Electrolyte Membrane Fuel Cell

Abstract

The effects of ozone at concentrations near 1000 vppm in air on the performance of a single polymer electrolyte membrane fuel cell (PEMFC) were investigated. Ozone was injected to the cathode alternately with far longer operation periods at 0.54 A cm–2 with ozone‐free air. Impedance spectra were recorded before, during and after exposure to ozone. After the first ozone injection, the loss in voltage was reversible, so were the changes in the resistances of the cell. Subsequent injection periods damaged irreversibly the PEMFC assembly. TEM observations with energy dispersive X‐ray spectroscopy analysis of the various parts of the PEMFC assembly together with the variations of the resistances allowed the ageing mechanism to be highlighted. Ozone was shown to allow partial dissolution of the Pt of the cathode catalyst. The charge transfer resistance was noticeably increased accordingly. Platinum re‐precipitated in the membrane bulk, and was also observed in the cathode‐side GDL. In addition, the likely degradation of the polymer near the triple‐point in the cathode could hinder gas solubility and water removal, as indicated by larger diffusion resistances.

Experimental investigation of pinhole effect on MEA/cell aging in PEMFC

“…Exponent n C varied usually from 0.96 to 1.0. The estimated equivalent capacitance of the cathode, estimated from the pseudocapacitance Q C [19], was found at 0.032 F cm À2 within 10% with no clear effect of the aging or of the RH level.…”

Heterogeneous Aging Within PEMFC Stacks

“…As exemplified in Figure 1, EI spectra of single cells consisted of two loops exhibiting significant overlapping. Interpretation of spectra was carried out using the equivalent circuit described in a previous paper [11]. Anode and cathode were treated separately, with a charge transfer resistance (R ct,a and R ct ) in parallel to constant phase element (Z CPEa and Z CPEc ).…”

Intriguing H2S Tolerance of the PtRu Alloy for Hydrogen Oxidation Catalysis in PEMFCs: Weakened Pt–S Binding with Slower Adsorption Kinetics

“…Kakati and Kucernak proposed a H 2 S mitigation strategy using ozone (O 3 ) to remove H 2 S in the PEMFC anode, and approximately 95% of the initial performance can be restored . Unfortunately, the injection of high-concentration O 3 into the fuel cell may cause the degradation of the membrane, leading to the decrease in cell performance . Shi et al found that the fuel cell performance can be completely restored through the potential cycling (0–1.4 V) approach, but this operation is rather complex and not practical in PEMFC application .…”