Scale-up of Metal-Supported Solid Oxide Fuel Cells
Authors: Dogdibegovic Emir , Shen Fengyu , Tucker Mike C 
Published: December 2020

Metal-supported solid oxide fuel cells (MS-SOFC) offer the advantages of low-cost structural materials (e.g. stainless steel), mechanical ruggedness, excellent tolerance to redox cycling, and extremely fast start-up capability. Because of rapid-start capability, MS-SOFCs may be well-suited for portable, ruggedized, fast-start, intermittent-fuel, transportation, or other unique and innovative applications. The LBNL approach focuses on symmetric-architectured, co-sintered, ScSZ-based MS-SOFCs with porous metal supports on both anode and cathode sides, and catalysts deposited into both electrodes via infiltration (Fig 1). These features provide for a mechanically rugged cell that can be processed with low-cost scalable techniques, and for high surface-area catalysts that are deposited after sintering, thereby avoiding interdiffusion or coarsening during cell sintering.
LBNL’s previous work on MS-SOFCs includes demonstration of A) Over 1000h operation in both hydrogen fuel cell and steam electrolysis modes [1,2], B) stable operation with direct internal reforming of ethanol-water blend fuel [3], C) startup within 10 sec for a bare cell and more than 200 rapid thermal cycles for a cell mounted on a test rig manifold [1,4], D) dynamic load-following with operating temperature fluctuating rapidly under load [5], and E) tolerance to multiple deep redox cycles [1].
Previous demonstrations were achieved with button cells in the range 3 to 7 cm2 total cell area. In this work, the MS-SOFC cell area is scaled up to 50 cm2 and higher, Fig 2. Scale-up of the stainless steel and zirconia cell architecture is straightforward. The cell structure is prepared by tapecasting large sheets and laser cutting to size, which is amenable to making any size or shape cell. Due to the symmetric nature of the cell architecture, the large cells remain flat after sintering.
Uniform catalyst deposition over a large area is, however, challenging. A number of improvements to the infiltration technique were developed, including: pre-oxidation of the stainless steel to enhance wetting of the aqueous catalyst precursor solution into the porous cell surface; development of highly concentrated Pr-oxide and Ni/doped-ceria precursor solutions that are shelf stable and low-viscosity; and, aerosol spray deposition of those solutions to uniformly coat the entire cell. With the improved infiltration, nearly identical performance for button and large cells is achieved. Spray deposition of shelf-stable aqueous solutions is also anticipated to be much more relevant to industrial-scale cell manufacturing, relative to LBNL’s previous molten salt infiltration technique.
Acknowledgements
The information, data, or work presented herein was funded in part by the Advanced Research Projects Agency – Energy (ARPA-E), U.S. Department of Energy under work authorization numbers 13/CJ000/04/03 and 18/CJ000/04/01. Funding for this work was provided by LBNL and the U.S. Department of Energy Advanced Manufacturing Office through a Technology Commercialization Fund grant number TCF-18-15740. This work was funded in part by the U.S. Department of Energy under contract no. DE-AC02-05CH11231.
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Figure 1