Mechanism of the cathode current collector on cell performance in a solid oxide fuel cell stack

In this work, we report a new design of the contact layer to investigate the significance and mechanism for the cathodic current collection. The single cells in a stack are covered with Ag paste on the cathode side, which exhibit slightly higher power density than that of the cell partially covered with Ag paste. The Ag paste is applied as a current-collecting layer on the cathode side at the corresponding position in contact with the punctuate structure of the interconnect. The difference in power densities between the two single cells is due to the in-plane electron transfer on the cathode surface. When the structure of the interconnect is changed from a convex punctuate structure to liner strips, the cell performance is governed by both gas flow rate and in-plane electron transfer; however, the latter plays a more important role than the gas flow rate. An appropriate arrangement of current collection at the cathode side is necessary to improve current collection and thus the cell performance inside the SOFC stack.