Lawrence Berkeley National Laboratory
Observation of Preferential Pathways for Oxygen Removal through Porous Transport Layers of Polymer Electrolyte Water Electrolyzers.
- Author(s): Satjaritanun, Pongsarun
- O'Brien, Maeve
- Kulkarni, Devashish
- Shimpalee, Sirivatch
- Capuano, Cristopher
- Ayers, Katherine E
- Danilovic, Nemanja
- Parkinson, Dilworth Y
- Zenyuk, Iryna V
- et al.
Published Web Locationhttps://doi.org/10.1016/j.isci.2020.101783
Understanding the relationships between porous transport layer (PTL) morphology and oxygen removal is essential to improve the polymer electrolyte water electrolyzer (PEWE) performance. Operando X-ray computed tomography and machine learning were performed on a model electrolyzer at different water flow rates and current densities to determine how these operating conditions alter oxygen transport in the PTLs. We report a direct observation of oxygen taking preferential pathways through the PTL, regardless of the water flow rate or current density (1-4 A/cm2). Oxygen distribution in the PTL had a periodic behavior with period of 400 μm. A computational fluid dynamics model was used to predict oxygen distribution in the PTL showing periodic oxygen front. Observed oxygen distribution is due to low in-plane PTL tortuosity and high porosity enabling merging of oxygen bubbles in the middle of the PTL and also due to aerophobicity of the layer.