A significant improvement of oxygen diffusion in catalyst layer based on hydrocarbon ionomer containing dimethyl silicone oil for PEM fuel cells

In this study, we significantly enhanced the oxygen diffusion in catalyst layer (CL) based on hydrocarbon ionomer containing dimethyl silicone oil (DSO) for polymer electrolyte membrane fuel cells. The enhancement of cell performance is attributed to increase of oxygen solubility in DSO as well as increase of hydrophobicity induced by DSO in CL. The oxygen diffusion flux in DSO is higher than that in water due to higher oxygen solubility. Furthermore, the addition of DSO in CL enhances the water transport from cathode to anode through polymer membrane due to hydrophobicity of DSO. This phenomenon helps to increase the hydration of polymer membrane and decrease the water flooding in cathode CL.

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► Catalyst layers (CLs) based on hydrocarbon ionomer containing dimethyl silicone oil (DSO) was evaluated to enhance the oxygen diffusion and reduce the ohmic resistance.
► Oxygen diffusion in DSO is higher than that in water due to higher oxygen solubility.
► Water transport from the cathode side to anode side is enhanced by adding the DSO, which helps in increasing the hydration of membrane and decreasing the water flooding in cathode CL.