Two-dimensional model of distributed charge transfer and internal reforming within unit cells of segmented-in-series solid-oxide fuel cells

摘要

This paper develops a computational model to represent details of reactive porous-media transport, elementary catalytic chemistry, and electrochemistry within unit cells of segmented-in-series solid oxide fuel cell (SIS-SOFC) modules. Because the composite electrode structures are thin (order of tens of microns), electrochemical charge-transfer chemistry can proceed throughout the composite electrode structures. Modeling such spatially distributed charge transfer is significantly more complex than modeling situations where the charge transfer can be represented at an interface between electrode and electrolyte. The present model predicts electric-potential fields of electrode and electrolyte phases, with the charge-transfer rates depending upon local electric-potential differences and the local gas-phase composition. The paper summarizes the underpinning physical and chemical models and uses examples to illustrate and interpret important aspects of SIS performance.