Abstract
Although water, not carbon dioxide, is the only substance that is exhausted from PEFC, water management inside PEFC is also important to improve its performance. To develop in-situ measurement techniques of water are needed to understand and control water, including water vapor. Authors first made an in-situ measurement by magnetic resonance imaging (MRI) to measure the spatial distribution of the water content within a polymer electrolyte membrane under operation1. This technique is valid for membrane only. It is extended to develop to measure water in gas diffusion layer using soft X-ray2. In-situ observation of liquid water transport in the microporous layer (MPL) and substrate layer of an operating PEFC was performed using high-resolution soft X-ray radiography.Recently, in order to achieve high current density in PEFCs, we developed thin GDLs to allow sufficient oxygen transport with suppression of concentration overvoltage caused by the liquid water accumulation inside. A thin self-standing GDL that consists of nano-fiber as a substrate layer and MPL is developed. The cell performance was improved in the case of the new GDL at high current density as shown in figure 1 compared to the case of the SGL25BC. Moreover, results of X-ray visualization showed that liquid water accumulation of new GDL was reduced. Tsushima, Kazuhiro Teranishi, S. Hirai, Electrochemical and Solid-State Letters, 7 , A269-A272 (2004)Deevanhxay, T. Sasabe, S. Tsushima, S. Hirai, J. Power Sources, 230, 38 (2013).Ishikawa, R. Aihara, H. Naito, K. Sakai, T. Sasabe, A. Tanioka, and S. Hirai, ECS Transactions, 109, 275 (2022) Figure 1
Published Version
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