Dense Membranes for Anode Supported all Perovskite IT-SOFCs

Bobba, Rambabu

Southern University Agricultural & Mechanical College

关键词: Perovskites;    Perovskite;    Cathodes;    X-Ray Diffraction;    Anodes;   

DOI  :  10.2172/937594
RP-ID  :  None
RP-ID  :  FG26-03NT41915
RP-ID  :  937594

美国|英语

来源: UNT Digital Library

【 摘 要 】

Innovative wet chemical synthetic techniques were employed to obtain highly ionic conducting dense perovskites, mixed conducting porous perovskites, and electronically conducting perovskite membranes to be as electrolyte, cathode, anode, and interconnect for assembling all perovskite IT-SOFC system. Processing conditions were optimized to obtain well sintered LSM, LSF, LSCF, LNF, and LCF for SOFC cell and stacks working at 600-800 C. Series of nanocrystalline bulk and thin films of La{sub 0.8}Sr{sub 0.2}Ga{sub 0.83}Mg{sub 0.17}O{sub 2.815}, LaSr{sub 0.2}Fe{sub 0.8}O{sub 3}, LaSr{sub 0.2}Co{sub 0.8}Fe{sub 0.2}O{sub 3}, La{sub 0.8}Ni{sub 0.7}Fe{sub 0.3}O{sub 3}, LaCr{sub 0.7}Fe{sub 0.3}O{sub 3} were prepared at very low temperatures and characterized using XRD, SEM, HRTEM, XPS, EXAFS, and EIS techniques. The influence of preparation techniques on the microstructure, grain-size and consequently on the electrical transport properties were investigated. Processing conditions, sintering temperature (1200-1500 C) and time severely affected the grain size (< 0.1 {micro}m to 10 {micro}m) and the resistance in all grain-boundary (3 k{Omega} to175 k{Omega}). Through investigations of A and B site doping in perovskite materials, we have reduced cathode-electrolyte interfacial resistance, will be very effective for the SOFCs operating {approx} 750 C. Epitaxial films of LiFeNiO{sub 3}, for SOFCs cathode were deposited on LaAl{sub 2}O{sub 3}, MgO, and YSZ single crystals by pulsed laser deposition (PLD) method, and characterized using advanced spectroelectrochemical techniques. The film orientations depend on the substrate planes. Surface morphology of the films also depends on the substrate orientations. These films showed different electrode properties depending on the orientations. The porous characteristic of the electrode materials are achieved by the combination of combustion and microwave sintering using SiC as susceptor (1200-1400 C). Concurrently, the other oxygen ionic/protonic conducting oxides (perovskites, pyrochlores, and apatites) were also prepared, characterized and understood the role in the development of reduced temperature SOFCs. In this HBCU/MI -research and educational project, we have emphasized the need to expand research opportunities for talented undergraduate and graduate African American students and junior faculty in the field of power sources based on nanoscience. We have paired the selected three undergraduate and two graduate students with full time research staff (PDF), for experimental measurements and discussions via preparing students to present the work in regional, national and international conferences. These students on an average made one presentation per year out side the SUBR campus. The effort in this project yielded 7 publications in refereed journals and about 15 in conference proceedings including NETL annual review meetings. Further, we have initiated a collaborative research and educational outreach project entitled 'Center for Hydrogen Energy and Advanced Power [CHEAP]' with University of West Indies-St. Augustine, Trinidad & Tobago (T &T).