Perovskite Oxide Anodes for SOFCs

School of Chemistry, University of St-Andrews, Fife, Scotland KYI 6 9ST, UK e-mail jtsi st-and.ac.uk 

Ishihara (ed.), Perovskite Oxide for Solid Oxide Fuel Cells, 

Fuel Cells and Hydrogen Energy, DOI 10.1007/978-0-387-77708-5 8, Springer Science-l-Business Media, LLC 2009 

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Some materials can match some requirements, but it is very hard to find a material that can match all the stringent requirements for SOFC anodes, particularly redox stability and conductivity. Materials with perovskite structure are promising, such as the redox stable anode (Lao.75Sro,25)Cro.5Mno.503 [54] and Sr2MgMoOg [58]. These materials exhibit performance approaching that of the traditional Ni-YSZ anode. Therefore, we can use a nickel-free redox-stable anode for SOFCs. With further optimization of the composition and microstructure, the performance of these materials may be further improved and hopefully replace the traditional Ni-YSZ anode in the future. There have been a number of recent reviews including the topic of oxide anodes where further information may be obtained [67, 68]... 

Similarly to the case of direct-oxidation anode materials, sulfur-tolerant anode materials based on sulfides [6, 7] or double-perovskite oxides have special requirements for their processing into SOFC layers. For example, nickel sulfide-promoted molybdenum sulfide is tolerant to high sulfur levels [7], However, it has a low melting temperature [6] that has resulted in the development of cobalt sulfide as a stabilizer of the molybdenum sulfide catalyst [6], CoS-MoS2 admixed with Ag has an even higher performance in H2S-containing fuels than in pure H2 [6]. However, processing methods such as PS, infiltration, or sol-gel techniques that can process... 

Similar efforts in solid-state electrochemistry for SOFC development focus on the exploration of new perovskites not only for the ORR but also for the anodic oxidation of hydrocarbons [182]. In this area, the discovery that Cu-based anodes present a viable alternative to the classical Ni-YSZ cermet anodes is particularly noteworthy [166, 183, 184], owing to the significant enhancement of performance by avoiding coke deposition. Similar important advances have occurred in the molten carbonate fuel cell (MCFC) area [9]. 

General While Ni/YSZ cermet is the most preferred anode material for SOFCs operating with hydrogen-containing fuels, there are several efforts to find alternative materials for the SOFC anode. Many studies on oxide anodes have been made for perovskite-related oxides. LaCr03 [230-237], LaFeOs [238], LaTiOs [239], and SrTiOs [240-243] systems are considered as possible alternative anode materials. 

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