Fabrication of wavy type porous triple-layer SC-SOFCs via experimental observation of curvature evolution during co-sintering

摘要

Wavy type Single Chamber Solid Oxide Fuel Cells (SC-SOFCs) are beneficial for improved triple phase boundary conditions contributing to higher performance, compared with planar type SC-SOFCs of the same diameter. This study presents a fabrication process for wavy type SC-SOFCs with a single fabrication step via co-sintering of a triple-layer structure. Curvature evolution occurs due to different sintering behaviour of each layer during the co-sintering process. In-situ observation of each layer during the co-sintering process allowed for minimisation of mismatched stresses to avoid unnecessary warping and cracking. Bilayers, consisting of NiO/CGO-CGO and CGO/LSCF, were co-sintered at 1200°C. In order to achieve the desired wavy type triple-layer structure, flexible green layers of each component were stacked up and laid on alumina rods to support the curvature during the process. In-situ observation, to monitor the shrinkage of each material and the curvature evolution of the structures, was performed using a long focus microscope (Infinity K-2). Monitoring of the curvature behaviour in real time minimised the development of undesired curvature in the triple-layer structure. Performance testing was carried out in a methane-air mixture (CH4:02) ratio of 1.