Characterization of PCFC-Electrolytes Deposited by Reactive Magnetron Sputtering; Comparison with Ceramic Bulk Samples ~ M. Arab Pour Yazdi 1,2 *, P. Briois 1,2 , S. Georges 3 , R. Costa 4 , A. Billard 1,2 1 IRTES-LERMPS, UTBM, Site de Montbéliard, 90010-Belfort cedex, France 2 Fuel Cell Lab, FR CNRS 3539, 90010-Belfort, France 3 LEPMI, INPG, ENSEEG, UMR CNRS 5631, 38402 Saint Martin d’Hères Cedex, France 4 Centre des Matériaux, Mines-ParisTech, BP87, Evry Cedex 91003, France Received September 28, 2012; accepted April 11, 2013; published online May 08, 2013 1 Introduction The recent concept of protonic ceramic fuel cells (PCFCs) has yield increasing developments [1, 2] due to its potential exploitation at rather lower temperature than that of solid oxide fuel cells (SOFCs), i.e., in the range 673–873 K [3, 4]. PCFCs present the same performances as those of current SOFCs but the reactivity and the cost of the stack component are strongly reduced [5]. Oxygen deficient perovskite structures ABO 3 , with A = Ba, Sr,... and B = Ce, Zr,..., have been shown to present very interesting proton conduction properties and chemical stability under different atmospheres [2, 6–9]. Oxygen vacan- cies are introduced into this perovskite structure by partial Abstract SrZr 0.84 Y 0.16 O 3–a (SZY16), BaZr 0.84 Y 0.16 O 3–a (BZY16), BaCe 0.8 Zr 0.1 Y 0.1 O 3–a (BCZY10), and BaCe 0.90 Y 0.10 O 3–a (BCY10) thin films with the thickness of lower than 6 micron are successfully deposited by reactive magnetron sputtering on alumina substrate covered by about 200 nm Pt 3 Ti collec- tor layer. The corresponding ceramic bulk samples are pre- pared by solid state reaction. In order to obtain dense BZY16 and BCZY10 samples, 1 wt.% ZnO was added before sinter- ing process. As deposited films are amorphous and crystallise under the expected crystal structure at different temperatures (e.g., SZY16 ≈ 623 K; BZY16 ≈ 423 K; BCY10 ≈ 873 K, and BCZY10 ≈ 873 K). SZY16 and BZY16 coatings are stable in air with respect to carbonation and hydration. BZY16 coat- ings require an in situ crystallization in order to avoid further cracking due to the tensile stress generation asso- ciated with the crystallization phenomenon, so they are deposited directly onto hot substrate (T substrate ≈ 523 K). BCZY10 amorphous coatings present a good chemical stabi- lity against carbonation in air up to 573 K but the coatings decompose in BaCO 3 and CeO 2 mixture after annealing treatment at around 873 K for 2 h in air, instead of the expected double substituted BaCeO 3 perovskite structure. Nevertheless, the crystallization perovskite structure is obtained after annealing treatment under vacuum to prevent the carbonation of the coating. BCY10 requires in situ crys- tallisation (T substrate ≈ 873 K) to obtain BaCeO 3 structure while avoiding the carbonation of the film. All the bulk sam- ples present the perovskite structure with a relative density higher than ∼80% and without trace of ZnO or BaCO 3 . Eighty percent of relative density was demonstrated to give a good compromise between porosity and grain boundary blocking effects. The electrical properties of the films and pellets are investigated by AC impedance spectroscopy in air. Conductivities of crystallised coatings are close but always significantly lower than those of ceramic bulk sam- ples of the same composition. Keywords: Pellet Samples, Proton Conductors, Reactive Magnetron Sputtering, Thin Films – ~ Paper presented at the 10th European SOFC Forum 2012, June 26–29, 2012 held in Lucerne, Switzerland. Organized by the European Fuel Cell Forum – www.efcf.com – [ * ] Corresponding author, mohammad.arab-pour-yazdi@utbm.fr FUEL CELLS 13, 2013, No. 4, 549–555 © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 549 ORIGINAL RESEARCH PAPER DOI: 10.1002/fuce.201200170