(180d) Low Temperature Sintering of Cathode-Supported Micro-Tubular Solid Oxide Fuel Cells Using Sintering Aids

Micro-tubular solid oxide fuel cells (SOFCs) with typical diameters ranging from sub-millimeter to a few millimeters offer several advantages such as facile sealing, high volumetric power density, and better endurance against thermal cycling and thermal shock. Cathode-supported micro-tubular SOFCs, in which a thick cathode layer serves as the structural support, allow for flexible cell-to-cell connections using inexpensive transition metals and also provide better stability under redox conditions. Additionally, cathode-supported cells with a one-end-closed configuration make it possible to use pressurized oxygen as the oxidant, which leads to better power generation performance. However, the fabrication of cathode-supported micro-tubular SOFCs has been found to be challenging because of the high co-sintering temperatures (â?¥1400 °C) required to obtain a dense electrolyte layer on top of the cathode support. At such high co-sintering temperatures, electrically insulating secondary phases are formed due to chemical reactions between cathode and electrolyte materials. Moreover, the high co-sintering temperature gives rise to coarsening of cathode particles and a very low porosity of the cathode support. Thus, it is desirable to reduce the sintering temperature of the electrolyte layer to achieve high-performance cathode-supported SOFCs. In the present work, we fabricated micro-tubular SOFCs with strontium-doped lanthanum manganite (LSM) cathode supports by multi-step dip coating and low temperature co-sintering techniques. NiO and Fe₂O₃ were used as sintering aids to obtain a dense yttria-stabilized zirconia (YSZ) electrolyte at lower co-sintering temperatures. The role of the sintering aids on densification behavior of the electrolyte and the properties of the fabricated micro-tubular SOFCs will be discussed in detail.