Optimization of current collection to reduce the lateral conduction loss of thin-film-processed cathodes

Abstract

To reduce the lateral conduction loss of thin-film-processed lanthanum strontium cobaltite (LSC) cathodes, the optimization of the current collection configuration is investigated. By increasing the number of the ribs in the metallic interconnects (MIC) and reducing the gap between the ribs, the lateral conduction distance at the cathode can be decreased, and as a result, cell performance can be improved by more than 30%. In addition, by changing the contact material from platinum to more resilient gold, the ohmic area specific resistance (ASR) is significantly reduced by the increase in effective contact area due to the deformation of the gold mesh. Furthermore, when a gold mesh with a finer grid size is used, the polarization ASR is decreased as well because the charge drainage can be improved by the enhanced current collection. With the optimization of the current collection, the cell performance is improved by a factor of 1.6 in comparison with that of the original test configuration. A power density of 562 mW cm−2 at 0.7 V and 600 °C is obtained with only approximately 2-μm-thick LSC cathodes.