Synthesis of Functional Ceramic Materials for Application in 2 kW Stationary SOFC Stacks

Abstract

This paper presents an overview of recent advances in the synthesis and preparation of solid oxide fuel cells (SOFCs) functional ceramic materials, focusing on low-/intermediary-temperature SOFCs. Novel synthesis processes for oxygen ion-conducting and mixed electronic and ionic conductors, fundamental to reduce the operating temperature of SOFCs were studied. Ni-Ce0.9Gd0.1O1.95 (Ni-CGO) anodes were successfully synthesized by the so called “one step synthesis”. La0.5Sr0.5Co0.8Fe0.2O3 (LSCF), Ce0.8Sm0.2O1.9 (SDC) and their mixture were produced as a cobaltite-based composite cathode by mixing powders synthesized by microwave-assisted combustion and the modified polymeric precursor method, respectively. Preliminary electrochemical activity tests with the synthesized electrodes were performed in electrolyte-supported SOFCs using commercially available 200 µm thick yttria stabilized zirconia (8YSZ) as electrolyte. The maximum power density of 52 mW/cm2 was reached at 850 °C. This result can be further improved replacing thick YSZ electrolytes by doped-ceria thin films, aiming at operation temperatures of 500–800 °C and power densities as high as 800 mW/cm2. The assembling of anode-supported cells with the configuration Ni-CGO/CGO (10 µm thickness)/LSCF-SDC are for applications in 2 kW stacks are currently under way.