Influence of Structural Modification of Micro‐Porous Layer and Catalyst Layer on Performance and Water Management of PEM Fuel Cells: Hydrophobicity and Porosity

Abstract

The influence of hydrophobicity and porosity of the catalyst layer (CL) and cathode microporous layer (MPLC) on water distribution and performance of polymer electrolyte membrane fuel cell (PEMFC) is investigated. Hydrophobicity of the layers is altered with the addition of PTFE (polytetrafluoroethylene) and mono‐dispersed polymer particles are utilized to introduce the macro‐pores with a diameter of 0.5 µm and 30 µm within the CL and MPLC, respectively. The treated materials are implemented in a specially designed fuel cell with an active area of 8 cm2 to perform operando high‐resolution neutron tomography measurements. At high current density and humid operating conditions, MPLs with higher PTFE content increase the overall water content of the cell. The more hydrophobic MPL (40 wt.% PTFE) performs below the corresponding reference MPL (20 wt.% PTFE), whereas the performance result of double layer MPLC gives hint for further potential improvements of such design. The local water saturation beneath the land regions with the presence of perforated CL and MPLC is increased which is explained by lower capillary pressure barriers of bigger pores. Despite a higher water content, the perforated layers enhance the performance of the cell at both dry (RH 70%) and humid conditions (RH 120%), indicating that the parallel two‐phase flow is facilitated where the oxygen is transported through small pores and the water is preferentially transported through the bigger pores.

Engineering Catalyst Layers for Next‐Generation Polymer Electrolyte Fuel Cells: A Review of Design, Materials, and Methods

“…[ 342 ] It has also been reported that water can preferentially fill the larger pores, which allows the smaller pores to transport the oxygen throughout the CL. [ 359 ] While these reports highlight the role of different size pores on water management further work is required to achieve a more complete understanding, particularly the role of pore size under different environmental conditions.…”

Alternative architectures and materials for PEMFC gas diffusion layers: A review and outlook

“…Perforation of both the MPS and the MPL was found to be provide the greatest improvement to the MEA performance [30]. A significant body of work has been undertaken on the effect of perforation of the MPL on PEMFC performance [141][142][143][144][145].…”

Research on the application of electrode materials for batteries

“…Water management problems [14]. GDL is the critical component of water management in PEMFC, and the battery will produce more water when working at a high current density.…”