In situ mapping of electrode potential in a PEM fuel cell

Here we describe an innovative fuel cell reference electrode array using a through-plate configuration, which makes possible for the first time accurate mapping of the variation in electrode potential across the active area of an operating polymer electrolyte membrane fuel cell (PEMFC). This configuration overcomes the major limitations of conventional fuel cell reference electrodes in that ohmic drop, potential distribution and electrode edge effects in the membrane are negated. The utility of the technique is neatly demonstrated in the study of catalyst support corrosion during fuel cell start-up, which is associated with movement of the air/fuel boundary through the anode flowfield.