BaCe0.85Y0.15O2.925 dense layer by wet powder spraying as electrolyte for SOFC/SOEC applications

Abstract

Y-doped barium cerate (BCY) is a protonic conductor showing an excellent conductivity that recently received increasing attention as an electrolyte in solid oxide cells operating at low–intermediate temperatures (<650°C). It has a poor thermal–chemical stability and this limits its practical applications. However, its attractive high conductivity makes BCY suitable to be inset between two other more stable thin layers to form a unique electrolyte in a protonic cell, with only a slight loss of electrochemical performance. In order to obtain a cost-effective and dense BCY electrolyte, the wet powder spraying (WPS) technique was considered in this study for the deposition of a thin (≈10μm) and dense BCY coating (BaCe0.85Y0.15O2.925) on a porous Ni-BCY substrate, to produce an anode-supported cell. To the authors' knowledge, only one paper recently appeared in the literature dealing with BCY deposition by WPS, but in that case the sprayed layer was isostatically pressed to obtain a dense layer.In this study, the optimization of suspension formulation, deposition conditions and sintering process allowed achieving a dense BCY layer without any additional step. The description of the spraying technique details and the parameters affecting a good film densification is reported. Furthermore, such a technique optimized for BCY can then be also considered for the production of thin electrolyte multilayers.