Structure-property-performance parametric investigation of the effect of platinum loading on RH-sensitivity of proton exchange membrane fuel cells

Relative humidity and platinum content are crucial factors that affect proton and oxygen transport behavior in the heterogeneous architecture of the fuel cell cathode. There is a need to understand the concurrent effects of these factors on fuel cell performance, considering recent commercialization efforts aimed at reducing the costs of fuel cell systems. This body of work presents a systematic account of the effect of cathode platinum loading and operating relative humidity on a matrix of structure, property, and performance parameters. Results demonstrate that RH-sensitivity is governed by the parameters of the polarization domain in which the system is operated, and in turn, by the inherent material properties that drive these parameters. Results further suggest that MEAs with lower Pt loadings are less responsive to fluctuation in humidification, compared to high platinum-loaded counterparts, and in turn could offer a broader operating window or support the usage of less complex auxiliary humidification systems. • A comprehensive SPP study is given on RH sensitivity across a range of Pt loadings. • SPP datasets are used in a 1-D model to deconvolute overpotentials. • RH sensitivity is linked to thickness, Pt accessibility, and catalyst structure. • Low Pt loadings show reduced RH sensitivity. • Low Pt loadings could enable a wider operational window.