Effects of Microstructural Functional Layers on Flat-Tubular Solid Oxide Fuel Cells

Abstract

The functional layer of a flat-tubular solid oxide fuel cell (SOFC) is examined using a three-dimensional microscale electrode model. SOFC electrodes essentially include two types of layers: a structural layer and a functional layer. The structural layers, which are the anode support layer and the cathode current collector layer, are composed of large particles with a high porosity that facilitates gas diffusion. The functional layers consist of small particles with a low porosity that increases the triple phase boundary (TPB) reaction area and reduces the activation overpotential. In the model, the particle diameter and functional layer thickness are adjusted and analyzed. The effects of the two parameters on the performance of the functional layer are monitored in the contexts of several multilateral approaches. Most reactions occurred near the electrode-electrolyte interface; however, an electrode design that included additional TPB areas improved the electrode performance. The role of the functional layer in a flat-tubular SOFC is examined as a function of the functional layer particle size and thickness. The performance of a cell could be enhanced by preparing a functional layer using particles of optimal size and thickness, and by operating the device under conditions optimized for these parameters.