Microporous Layers with Different Decorative Patterns for Polymer Electrolyte Membrane Fuel Cells

Abstract

To optimize the interface of the catalyst layer (CL) and gas diffusion layer (GDL) in polymer electrolyte membrane fuel cells (PEMFCs), microporous layers (MPLs) with different decorative patterns were prepared. Carbon paper treated with polytetrafluoroethylene was used as a substrate for the coating of MPLs. To accelerate water removal and gas permeation, ammonium chloride was utilized to improve the porous structure of MPLs. Owing to the recrystallization and pyrolysis of ammonium chloride with different contents, the surface of MPLs exhibited point-, line-, and flowerlike patterns. Membrane electrode assemblies (MEAs) were assembled to evaluate the performance of MPLs with different decorative patterns. From measurements, an MEA containing a porosity-graded MPL (MPL-G) with a flowerlike pattern exhibited the best electrochemical performance. It is because that graded porosity accelerates the removal of excessive water. The flowerlike pattern facilitates the diffusion of the reactant gas at the interface of the catalyst layer and MPL. With the measurement of segmented cell technology, such MEAs revealed an improved redispersion of reactant gases. Furthermore, the produced water was compressed to the gas outlet, providing a larger active region for reaction. These results indicate that pattern design of MPLs is a promising strategy to improve the mass-transfer efficiency at the interface of the catalyst layer and gas diffusion layer.

Proton Exchange Membrane Fuel Cells (PEMFCs): Advances and Challenges

“…The effect of the nature of the substrate, carbon black, and PTFE loading in the different carbonaceous phases in the microporous layer (MPL) is usually chosen to modify their surfaces with hydrophobic materials for better H 2 O removal ability [ 389 , 390 ]. The effect of the hydrophobicity of microporous layers with different decorative patterns to optimize the interface of the catalyst layer and gas diffusion layer (GDL) in the performance of PEMFC was investigated [ 391 ]. Results concluded that the microporous layer could be considered as a promising strategy to improve the mass transfer efficiency at the interface of the catalyst layer and gas diffusion layer.…”

Microporous Layer Containing CeO2-Doped 3D Graphene Foam for Proton Exchange Membrane Fuel Cells at Varying Operating Conditions

“…As the MPS, a carbon paper (TGP-H-060, Toray) was treated with a poly(tetrafluoroethylene) (PTFE) suspension (DISP30, DuPont) to avoid flooding in the interlaced carbon fibers. 30 The MPL slurry was obtained by mixing acetylene black and PTFE suspension in deionized water with a mass ratio of 7:3. The additive amount of CeO 2 in the above slurry was 10 wt %.…”

Managing the Pore Morphologies of Microporous Layers for Polymer Electrolyte Fuel Cells with a Solvent-Free Coating Technique

“…In addition, MPLs with a porosity gradient experience internal capillary pressure. Similarly, other researchers have shown that MPLs with a porosity gradient introduced using ammonium chloride exhibit electrochemical performance superior to that of MPLs with a uniform pore-size distribution. − The addition of thermally expandable GPs has been reported as another approach for the fabrication of MPLs with a porosity gradient . MPLs with gradient hydrophobicity have also been effective for draining water accumulated in GDLs .…”

“…MPLs with gradient hydrophobicity have also been effective for draining water accumulated in GDLs . To fabricate MPLs with gradient features requires at least one step of the wet-coating process to be repeated. ,,− However, repeated drying and annealing processes for the fabrication of multilayers significantly increase the product cost and the environmental impact.…”