Two-phase transport mechanism through the highly-penetrative surface crack in the micro-porous layer of polymer electrolyte fuel cells

Abstract

With the exponential development of renewable energy production and consumption, there have been increased demands for electrochemical energy storage and conversion devices using hydrogen as the energy carrier. Among various, the PEFC is receiving spotlights as one of the key technologies in the transportation sector, which account for more than 30% of whole energy consumption. To increase the utilization ratio of the catalyst and the efficiency of the reactant, the structure of the electrode and gas diffusion layer has repeatedly become more complex and smaller. In particular, three dimensional nano-structure of the gas diffusion layer is intersected site of the reactant and product. Liquid water is condensed into a pore of several hundred micrometers at the interface between the catalyst layer and microporous layer that formed in the vertical direction of the channel at low temperature, high humidity, and/or high current density. Herein, the crack was formed in a microporous layer to completely separate the pathway of the reactant and products. The penetrating-type crack is an expressway of two-phase transport, and non penetrating-type crack plays a role as liquid storage and is proved via an electrochemical and tomographical methods.