One-Step Flash Sintering of Solid Oxide Fuel Cells

Solid oxide fuel cells (SOFCs) are ideally suited for environmentally benign conversion of chemical energy in hydrocarbons to electricity.  While medium scale SOFC power systems in the hundreds of kWe have been demonstrated, larger scale application of such systems have been hobbled by still too high cost.  Reducing the manufacturing costs of single cells is an important goal as one step towards commercialization.   Previously, we demonstrated a simplified process to manufacture the complex multilayer architecture of anode supported single cells in a single high temperature firing step, after deposition of the anode active layer, electrolyte, cathode active layer, and cathode current collector layers serially by screen printing on to an anode substrate fabrication by a process known as high shear compaction.  In this paper, we present a novel manufacturing process in which the basic green-state cell is fabricated using the same steps as before, but in which the high temperature conventional sintering step is replaced by a technique known as flash sintering which reduces time at temperature by up to an order of magnitude, thereby resulting in significant savings in time and electrical energy expended. We present details of this new process, cross-sectional microstructures of cells fabricated using this technique, and compare the power densities of the cells processed by flash sintering with the prior co-fired process.