Progress in Metal-Supported Solid Oxide Fuel Cells and Electrolyzers with Symmetric Metal Supports and Infiltrated Electrodes

Abstract

The LBNL metal-supported solid oxide cell architecture contains zirconia electrolyte and porous backbones co-sintered between porous stainless steel supports. Advantages of this design include low-cost structural materials, mechanical ruggedness, excellent tolerance to redox cycling, and extremely fast start-up capability. With infiltrated catalysts, high performance is also achieved: 1.5 W/cm2 with hydrogen fuel and 1.3 W/cm2 with internal reforming of ethanol fuel at 700 °C; 2.6 A/cm2 electrolysis current density at 1.3V and 50% steam/50% hydrogen at 700°C. Recent approaches to mitigating catalyst coarsening and Cr deposition within the cathode stabilize the microstructure during operation. The degradation rate is improved to 2.3% kh-1 at 700°C in fuel cell mode. Electrolysis operation, however, results in higher degradation rate. Preliminary effort to fabricate metal-supported cells with proton conducting electrolyte is successful for La0.99Ca0.01NbO4 electrolyte, and specific challenges for BaZr0.7Ce0.2Y0.1O3-δ electrolyte are determined.