(Invited) Metal-Supported Solid Oxide Fuel Cells and Electrolyzers for Low-Cost, Robust, Rapid-Start Systems

Abstract

This talk will provide an overview of performance, durability, and applications of metal-supported solid oxide fuel cell and electrolysis cell technology developed at Lawrence Berkeley National Laboratory (LBNL). The unique LBNL symmetric cell architecture design, with thin zirconia ceramic backbones and electrolyte sandwiched between porous metal supports, offers a number of advantages over conventional all-ceramic cells, including low-cost structural materials (e.g. stainless steel), mechanical ruggedness, excellent tolerance to redox cycling, and extremely fast start-up capability.MS-SOFC performance with a variety of fuels will be presented, including hydrogen, ethanol, natural gas, and simulated reformates. The impact of the presence of carbon and internal reforming catalysts on the durability of the cells will be examined. In particular, oxidation of the stainless steel supports in the presence of carbon is analyzed. Scale-up from button cells to 50cm2 will be presented.The case for use of MS-SOECs for dynamic electrolysis operation will be made. Detailed analysis of degradation modes over 1000h of operation with 50/50 steam/H2 informed efforts to improve durability through the use of coatings and catalyst processing techniques.In addition to our long-standing development of zirconia-based metal-supported cells, recent efforts on metal-supported proton-conducting cells are ongoing. Co-sintering of 400-series stainless steel and BZCY-type proton conductors presents a number of challenges, including: Ba evaporation in reducing atmosphere, over-densification of steel at the high temperatures (>1400°C) required for BZCY processing, mismatch of metal and ceramic sintering behavior, and migration of Cr and Si from the steel support into the BZCY layers. Feasibility of new approaches to overcome these challenges will be discussed.