Fabrication and Performances of a Small SOFC Stack Using Doped Lanthanum Gallate Electrolyte

Abstract

A 4-cell tubular solid oxide fuel cell (SOFC) stack using strontium- and magnesium-doped lanthanum gallate electrolyte was built and electrically tested. Doped lanthanum gallate is a potential alternative to the commonly used yttria stabilized zirconia (YSZ) in SOFCs for use at intermediate temperatures (typically 600-750°C). La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 2.8 (LSGM) powder was mixed with a polymer-based binder system and extruded into tubes. After sintering, the electrolyte tubes were approximately 6 mm outside diameter, 0.55 mm wall thickness and 100-200 mm long. The tubes were then fabricated into single SOFCs, using optimized La 0.6 Sr 0.4 CoO 3 (LSCo) cathode, Ce 0.8 Sm 0.2 O 1.9 (SDC) interlayer, and Ni anode. The electrical performances of the single cells, as well as the 4-cell stack, were tested using dry hydrogen as a fuel. A power of 2.5-3 W per cell and 10 W for the 4-cell stack were obtained at 800°C. The maximum power density of the LSGM supported single tubular fuel cell with LSCo cathode, SDC interlayer and Ni anode was 372 mW/cm 2 at 800°C. This paper will present the fabrication procedure and parameters, single fuel cell, and 4-cell stack performance.