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

摘要

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-Ce_(0.9)Gd_(0.1)O_(1.95) (Ni-CGO) anodes were successfully synthesized by the so called "one step synthesis". La_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_3 (LSCF), Ce_(o.8)Sm_(o.2)O_(19) (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/cm~2 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/cm~2. 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.