Preparation of SDC electrolyte thin films on dense and porous substrates by modified sol–gel route

Nanocrystalline fluorite type samarium doped ceria (SDC) electrolyte thin film for intermediate temperature-solid oxide fuel cells (IT-SOFCs) application were prepared on the dense and porous substrates at low temperatures of 573–1373 K using a novel citrate sol–gel route combined with a sol suspension spray coating technique. Thermogravimetric analysis showed that the decomposition of the citrate gel film and the initial crystallization of the SDC occurred at a low temperature of about 590 K. XRD examination revealed that the annealing of the green film at temperatures of 573–1373 K provided cubic nanocrystalline SDC phase. The crystallite sizes were in the range of 9–19 nm. Microscopic observations indicated that the derived film was homogeneous, dense and crack-free without pinholes. The desired thickness for preparation of thin electrolyte films from hundreds of nm to several μm should be controllable and feasible by repeating the simple and inexpensive citrate sol–gel spray coating process.