Influence Factors of Platinum Dissolution in Proton Exchange Membrane Fuel Cells: A Sensitivity Study
Julian Stiegeler, Thomas Mittermeier, Leonidas Tsikonis, Thilo Lehre, Severin Vierrath
Abstract
Polymer electrolyte fuel cells for heavy-duty applications require lifetimes beyond 30,000 h, which poses a durability challenge. In this study, we investigated the influence of various factors on loss of electrochemically active surface area (ECSA) in the cathode, which is a major limiting factor. We derive a parameter range from simulated drive cycles showing that the voltage ranges between 0.70 and 0.85 V and that the cells are in idle state at upper potential limit (UPL) most of the time. We evaluate the influence and interaction of UPL, lower potential limit (LPL), temperature, relative humidity, and cycle time on ECSA and performance at four different operating conditions after 10,000 potential cycles based on 25 experiments. The results indicate that UPL and the hold time at UPL have the strongest impact on degradation, while LPL has a small impact, which does not increase below the potential of full platinum reduction (0.55 V) or hold times longer than 2 s. Furthermore, the interaction of humidity with other factors becomes significant for long experiment times. In summary, the findings of this work can serve as guidelines for minimizing ECSA loss, e.g. by keeping the fuel cell in a benign operation regime via systems control.