Rapid and Low-Energy Fabrication of Symmetrical Solid Oxide Cells by Microwave Methods

Solid oxide fuel cells are highly efficient, low-emission, and fuel-flexible energy conversion devices that can also run in reverse as solid oxide electrolysis cells, converting CO 2 and/or H 2 O to useful fuels and pure O 2 . Our team has recently developed a highly promising mixed conducting oxide catalyst (La 0.3 Ca 0.7 Fe 0.7 Cr 0.3 O 3-δ ) that can be used at both the anode and cathode in either the fuel cell or electrolysis mode in a lower-cost symmetrical cell. However, there is still a need to improve material processing and cell manufacturing methods in this field. Here, we report, for the first time, fabrication of a symmetrical solid oxide cell, based on our very promising catalysts, using rapid, low-cost, low-energy, and green microwave (MW) processing techniques. These cells were fabricated with MW-sintered powders and were then MW-sintered without the use of any MW susceptors inside the electrode layers or any additional presintering steps. The catalyst layers show very stable nanostructures and do not delaminate, and the cells exhibit reaction rates that are similar to those obtained using normal ceramic processing methods. Importantly, the powder preparation and cell sintering steps, carried out using MW methods, require only ca. 1/3 and 1/9 of the time/energy, respectively, versus those required in traditional furnace methods, thus translating to significant cost savings.