© The Author(s) 2015. We report an analytical solution for the membrane potential in a PEM fuel cell which consist of a half-plane (semi-infinite) anode and a large-area (infinite) cathode. Mathematically, the problem is analogous to the Gouy-Chapman problem for the potential distribution inside the diffuse double layer at a flat metal/electrolyte interface. An expression for the characteristic length l<inf>∗</inf> of the membrane potential variation in the anode-free domain is derived. This expression suggests a minimum distance 3l<inf>∗</inf> between the anode edge and a reference electrode at which the potential of the reference electrode yields the cathode overpotential in the working domain of the cell.
Kulikovsky, A. A., & Berg, P. (2015). Positioning of a Reference Electrode in a PEM Fuel Cell. Journal of The Electrochemical Society, 162(8), F843–F848. https://doi.org/10.1149/2.0231508jes