Investigation of effects of hydrophilic micro-porous layer on liquid water behavior by X-ray imaging

[摘要] In this study, X-ray imaging and electrochemical measurements were simultaneously performed to clarify the effects of the properties of micro-porous layers (MPLs) on the i-V performance and the liquid water behavior (LWB) of polymer electrolyte fuel cells (PEFCs) operating at a cell temperature of 50 degrees C and relative humidity of 80 %. To evaluate the effects of wettability, structure and thickness of MPLs, four types of MPLs were tested. The results demonstrate that LW accumulation (LWA) in the substrate part decreased in hydrophilic MPLs by a mechanism that sucks up liquid water and evaporates it. Moreover, MPLs using carbon fiber (CF) material demonstrated less LWA than those using carbon black (CB). Furthermore, the difference in MPL thickness significantly affects the cell performance and LWB, indicating that the MPL thickness optimization is necessary. These results indicates that hydrophilic MPLs effectively suppress LWA and enhance the oxygen transport.

[发布日期] 2021-09-30

[关键词] PEFCs;Hydrophilic MPLs;X-ray visualization