Colloidal Processing of Y0.08Zr0.92O2/La0.80Sr0.20MnO3 Semi-Cells Using a Sr-Doped Lanthanum Manganite Synthesized by a Citrate Route.

Paloma Recio,Rodrigo Moreno,Carmen Alcázar

doi:10.3390/ma14247831

Paloma Recio, Rodrigo Moreno + Show 1 more

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https://doi.org/10.3390/ma14247831

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Abstract

In this paper, the interface between yttria stabilized zirconia (Y0.08Zr0.92O2, YSZ) electrolyte and Sr-doped lanthanum manganite (La0.80Sr0.20MnO3, LSM) cathode for solid oxide fuel cells (SOFCs) is studied. For such a purpose, the combination of a suitable synthesis route for obtaining fine powders and simple aqueous colloidal shaping routes is proposed. The synthesis of nanosized particles of La0.80Sr0.20MnO3 by a citrate route and their full characterization, including the colloidal stability and the densification and phase development determined by X-ray diffraction and electron microscopy at different temperatures, is reported. In a second step, YSZ tapes were obtained by aqueous tape casting and used as substrates for the preparation of LSM coatings by dip-coating using aqueous slurries. YSZ tapes were used either in the green state or after a pre-sintering treatment. Co-sintering at 1350 °C led to a sharp interface with excellent adhesion, also achieved when coating pre-sintered tapes. In both cases, the substrates are dense and the coatings are porous, with thicknesses of 85 and 60 μm for green and pre-sintered tapes, respectively. No diffusion of Zr and Y occurs at the LSM layer, but some diffusion of La and Mn towards the YSZ layer takes place.

Highlights

La1−xSrxMnO3 (LSM) oxides have received increasing attention in the last years thanks to their complex chemistry that allows the synthesis of a broad number of compositions, the excellent electrical and magnetic properties, and the good mechanical behavior, which make them suitable for a variety of applications in several technological sectors such as medicine, energy, chemistry, and magnetism [1,2,3,4]
The calcination temperature determines the development of new phases as well as the retention of undesired phases, such as the original nitrates or the hydroxides formed at early temperatures
Three exothermic effects with their maximum peaks centered at temperatures of 292, 345, and 405 ◦C can be detected, which are related to the destruction of the organic compounds involved in the Pechini synthesis route

Summary

Introduction

La1−xSrxMnO3 (LSM) oxides have received increasing attention in the last years thanks to their complex chemistry that allows the synthesis of a broad number of compositions, the excellent electrical and magnetic properties, and the good mechanical behavior, which make them suitable for a variety of applications in several technological sectors such as medicine, energy, chemistry, and magnetism [1,2,3,4]. The most extended applications are related to their high catalytic activity in automotive exhaust control and for the elimination of CO pollution [5,6], the ferromagnetic properties of manganite nanoparticles that exhibit very low Curie temperatures [7], and the production of cathodes for solid oxide fuel cells (SOFCs) [8,9,10]. Among the cathode materials for SOFCs, manganites are probably the most popular because of their high electronic conductivity and the chemical stability and compatibility with the most frequently used electrolyte (zirconia stabilized with 8 mol% yttria, YSZ). The development of different routes for the synthesis of manganites with tailored compositions has attracted the interest of the scientific community

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