Determination of CL Ionomer Conductivity

The electrochemical reactions in a polymer electrolyte fuel cell (PEFC) necessitates the transport of protons, electrons and pertinent neutral species (oxygen, water, and/or hydrogen) to/from the active reaction sites. Proton conduction often competes with neutral species transport in controlling the overall reaction rate. Depending on the proton conductivity, the CL thickness, and the current density (reaction rate), significant distribution of the protonic potential and, by extension, the overpotential across the CL can occur. Under such conditions, the “effective ” utilization of CLs can be significantly impacted. Since ionomer is the proton-conducting phase in a PEFC CL, the determination of the CL ionomer conductivity is important for diagnosing its performance characteristics