Fast and Reliable State-of-Health Model of a PEM Cathode Catalyst Layer

Abstract

Long-term stability of polymer electrolyte membrane fuel cells under dynamic operation still has a high potential for optimization, specifically for use in the automotive industry. This stability is especially affected by the degradation processes taking place in the cathode catalyst layer and hence should be fully understood. In this work, we develop a fast and reliable state-of-health model of the cathode catalyst layer, incorporating the electrochemical degradation processes related to anodic and cathodic platinum dissolution, oxidation, Pt loss due to ion diffusion, carbon corrosion and place exchange mechanisms as well as their interaction. For the purpose of validation, the model is developed alongside a comprehensive experimental data set. A detailed parameter study taking into account temperature, relative humidity and load profile dependency was carried out. A good agreement between model and experiment was found for load ranges between 0.6 and 0.95 V. Further, good approximation of the active surface area loss for cell temperatures between 60°C and 90°C and relative humidity between 30% and 100% were achieved.

Physical Modeling of Catalyst Degradation in Low Temperature Fuel Cells: Platinum Oxidation, Dissolution, Particle Growth and Platinum Band Formation

“…24 The kinetic multi-step model was validated against cyclic voltammetry and potentiostatic oxide growth measurements. Very recently, Schneider et al 25 developed a zero-dimensional catalyst degradation model which includes platinum oxidation, place-exchange, dissolution, Ostwald ripening as well as platinum loss due to carbon corrosion and platinum ion diffusion into the membrane. The model was validated with ECSA measurements for various operating conditions and the contribution of the various mechanisms on the overall ECSA loss was investigated.…”

Joint Component Sizing and Energy Management for Fuel Cell Hybrid Electric Trucks

“…2) Degradation Model: During the FC operation, a degradation takes place, the rate of which depends on internal conditions, such as temperature, pressure, membrane water content, etc. Membrane electrode assembly degradation, which is mainly due to the fading of catalyst layer [36], proton exchange membrane [37] and gas diffusion layer [38], is recognised as the main factor that influences performance and lifetime [39], [40], [41]. This kind of degradation is closely determined by the load profile that is often classified into 5 categories [22], [42], [43], including constant load current, current cycling, extra-low current, extra-high current and open-circuit voltage.…”

Spatially Resolved Electrochemical Impedance Spectroscopy of Automotive PEM Fuel Cells

“…The effect of reactant contributions in a line vertical to the flow channels was investigated by Schneider et al. [22] . They found that mass transport limitations underneath flow field ribs significantly affect cell performance at high cell currents.…”

“…Scanning electrochemical microscopy-based measurements are, for in-stance, used to characterize fundamental processes in half cells with high resolution, but it lacks functionality for industrial fuel cells [16][17][18] . For a complete membrane electrode assembly (MEA), the local impedance response is usually recorded by either measuring with a segmented fuel cell [19][20][21][22][23] or by adding a printed circuit board (PCB) to the setup [24][25] . Segmented cells are based on segmented flow fields and current collectors, with each segment being electronically isolated from its neighbors.…”

“…The effect of reactant contributions in a line vertical to the flow channels was investigated by Schneider et al. [22] They found that mass transport limitations underneath flow field ribs significantly affect cell performance at high cell currents. Gerteisen et al [21] analyzed the influence of flow configuration, flow rate, and relative humidity on the local highfrequency resistance.…”