Electrophoretic Deposition of Dense Sr- and Mg-Doped LaGaO 3 Electrolyte Films on Porous La-Doped Ceria for Intermediate Temperature Solid Oxide Fuel Cells F. Bozza 1 , R. Polini 1 *, and E. Traversa 1 1 Dipartimento di Scienze e Tecnologie Chimiche, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy Received February 29, 2008; accepted April 30, 2008 1 Introduction Solid oxide fuel cells (SOFCs) have attracted a considerable attention due to their high-energy conversion efficiency and fuel flexibility [1, 2]. SOFCs use ceramic substances as electrolytes and have shown considerable promise for a variety of applica- tions ranging from mobile devices for transport to stationary power plants. The system efficiency of SOFCs can be further enhanced up to 60% or more by hybridisation with a gas turbine. SOFCs advantages include their solid-state design and no water management problem. A standard tubular SOFC using yttria- stabilised zirconia (YSZ) as an electrolyte requires operating temperatures around 1,000 °C, resulting in a series of severe problems such as chemical reactions between different materi- als, cracking during thermal cycling, gas leaking and other func- tioning and maintenance issues. Planar cell design allows to operate YSZ base SOFCs at around 800 °C with above 1 W cm –2 power density [3]. A significant boost to the reduction in the cost of planar SOFCs would be achieved if readily available and easily formed metals, such as ferritic stainless steels, could be used for the interconnect plate and gas manifolding. However, the problems of high temperature corrosion mean this is only realistic if the operating temperature is reduced to temperatures below 800 °C. A further reduction of the operating temperature would also lead to an increase in stack reliability and lifetime. The stack performance is strongly related to the oxygen ion conductivity of the electrolyte. At temperatures lower – [ * ] Corresponding author, polini@uniroma2.it Abstract The application of the electrophoretic deposition (EPD) tech- nique to the preparation of dense La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 2.8 (LSGM) electrolyte films for intermediate temperature solid oxide fuel cells (IT-SOFCs) was investigated. Suspensions of LSGM were prepared in acetone + I 2 +H 2 O dispersion media. The effects of water and iodine content, of the applied voltage, and of powder loading on the EPD rate were systematically studied using metallic substrates (Pt and stainless steel). This allowed to identify the suitable set of EPD process parameters that were used to deposit LSGM films on tape-cast composite electrodes, composed of lantha- num-doped ceria (La 0.4 Ce 0.6 O 2–x , LDC), polyvinylidene difluoride (PVDF) and carbon powders. After EPD, dense and crack-free 15 lm thick LSGM films were obtained on porous LDC by co-firing in air at 1,490 °C. Line profile ana- lyses performed by energy dispersive X-ray spectroscopy (EDS) did not reveal any interdiffusion of ions across the LSGM/LDC interface. The chemical and structural compat- ibility of LSGM with LDC was also checked by heat treating a mixture of the two powders (1:1 weight ratio) using the same thermal cycle as that of the LDC/LSGM bi-layer co-fir- ing at 1,490 °C. EPD has thus proven to be a viable way for manufacturing anode-supported LSGM electrolyte films. Keywords: Electrophoretic Deposition, Electrolyte Proces- sing, Lanthanum Gallate, Solid Oxide Fuel Cells 344 © 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim FUEL CELLS 08, 2008, No. 5, 344–350 ORIGINAL RESEARCH PAPER DOI: 10.1002/fuce.200800022