Key factors impacting liquid water behaviors across the interfaces of the multiple-scale porous transport layers in PEMFCs

It is of the utmost importance to facilitate the rapid drainage of the product liquid water in order to guarantee the delivery of sufficient reaction gas to the reaction zone and ensure the optimal operation of the proton exchange membrane fuel cell (PEMFC). The pore structure within the porous transport layer serves as pathways for the removal of liquid water from the membrane electrode assembly (MEA). The majority of existing studies on this topic focus on the transport of liquid water within a single component of the MEA. However, the mechanisms of liquid water transfer across scales and interfaces in the porous transfer layer remain relatively understudied. This paper presents a review of the primary factors influencing the distribution and transport behaviors of liquid water across the CL/MPL, MPL/GDB, and GDB/GC interfaces. These include the structural characteristics and physical parameters of the interfaces and relevant components, as well as the operating conditions of the PEMFC. The impacting mechanism is also introduced. The objective of this review is to provide insights into the design and optimization of porous transport layers from a water management perspective, with the aim of improving the durability and power density of PEMFCs.