Experimental and Simulated Evaluations of Current Collection Losses in Anode-Supported Microtubular Solid Oxide Fuel Cells

Anode-supported microtubular solid oxide fuel cells (SOFCs) with a diameter on the millimeter scale can generate high electrical power density. However, the longer the cell, the larger are the losses associated with current collection, because the current path is along the length of the microtubular cell. In this study, the experimental and simulated evaluations were conducted to estimate the current collection losses of the microtubular SOFCs with various geometries (the anode thickness and length) and several species of current collectors on the cathode. The cell with 2 mm in diameter and 30 mm in cathode length without a current collector on the cathode had a large ohmic loss. The simulated evaluation using a simple equivalent circuit model suggests the low current density in the wide area without a current collector for the microtubular cell, which causes the decrease in the cell performance. The increase in the electrical conductivity of a current collector on the cathode was effective to improve the current density in the entire microtubular cell. The cathode current collection is significantly important to obtain high cell performance for the long anode-supported microtubular SOFCs. (C) 2013 The Electrochemical Society. All rights reserved.