FABRICATION AND PERFORMANCES OF A SMALL SOFC STACK USING DOPED LANTHANUM GALLATE ELECTROLYTE

摘要

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℃). 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℃. 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℃. This paper will present the fabrication procedure and parameters, single fuel cell, and 4-cell stack performance.