In-situ measurement of humidity distribution and its effect on the performance of a proton exchange membrane fuel cell

Understanding the internal water distribution in proton exchange membrane fuel cell (PEMFC) is critical to the development of high-performance PEMFCs. In this study, the cathode flow field is divided into 9 areas, and the relative humidity under different conditions is measured in-situ by using microsensors embedded in the cathode flow field plate. Polarization curves are measured and electrochemical impedance spectroscopy is carried out under different conditions. The results show that the relative humidity has a significant effect on the internal resistance of PEMFCs. When the inlet gas is not humidified, too high of a temperature will lead to low relative humidity and membrane dehydration. Increasing pressure and cathode humidification can alleviate this problem. However, the relative humidity of the outlet area is close to 100% when the cathode back pressure is 100 kPa, and a too high relative humidity will result in flooding in the cathode channel. Moreover, the degree of corrosion of the carbon support in the catalyst is closely related to the water concentration in the cathode, and the water management downstream of the flow field is particularly important . (c) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Understanding internal water distribution is crucial for developing high-performance proton exchange membrane fuel cells (PEMFCs). This study divided the cathode flow field into 9 areas and measured relative humidity in real time using microsensors. The results showed that relative humidity significantly affects the internal resistance of PEMFCs, and strategies like increasing pressure and cathode humidification can alleviate related issues. Additionally, the degree of corrosion in the catalyst's carbon support is closely related to water concentration in the cathode, highlighting the importance of water management downstream of the flow field.