Production of high conductivity composite zirconia solid oxide electrolytes with good mechanical strength through net-shape

Abstract

Yttria- and scandia-doped zirconia composite solid electrolytes were prepared by impregnation of a porous tetragonal 3 mol% Y₂O₃ zirconia matrix with a solution of scandium nitrate in a net-shape type process. The resulting composite exhibited both high conductivity (0.01 S cm⁻¹at 903 K) and good mechanical strength and fracture toughness. This excellent performance can be attributed to the achievement of a favourable inhomogeneous structure of the core–shell type. Grain surfaces are enriched with scandia dopant to improve both crystal and grain boundary conductivities with formation of cubic zirconia at these interfaces, whilst retaining the small grain size of the tetragonal phase, which optimises mechanical properties and favours production of thin electrolytes.