iScience (Dec 2020)

Observation of Preferential Pathways for Oxygen Removal through Porous Transport Layers of Polymer Electrolyte Water Electrolyzers

  • Pongsarun Satjaritanun,
  • Maeve O'Brien,
  • Devashish Kulkarni,
  • Sirivatch Shimpalee,
  • Cristopher Capuano,
  • Katherine E. Ayers,
  • Nemanja Danilovic,
  • Dilworth Y. Parkinson,
  • Iryna V. Zenyuk

Journal volume & issue
Vol. 23, no. 12
p. 101783

Abstract

Read online

Summary: 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.

Keywords