Performance modelling of intermediate temperature solid oxide cells applied as electrochemical air separation unit

Abstract

Oxygen production is a highly energy-consuming process, above all at the required purity increase. The state-of-the-art application consists of cryogenic distillation widely used for a high production scale, while the adsorption and polymeric membrane technologies are more convenient for low demands without reaching the performance of the first yet. Solid oxide cells are a promising alternative since the performance in terms of the energy demand and the purity degree is independent from the system capacity, making them suitable for several application fields. Nevertheless, the technology readiness level is still too low for commercial use, requiring further improvements on material performance and durability, cell design and process management. Performing a detailed multiscale feasibility analysis, the work discusses the use of planar stacked cells working at intermediate temperatures and atmospheric pressure. High-performing co-doped double perovskite electrodes allow for optimising the separation kinetics. At the air side, the molecular oxygen dissociates through an externally applied potential into ions that migrate inside a highly anionic conductive electrolyte and reconvert to O₂ at the pure oxygen side.