Ceria-based solid electrolyte exhibits superior mechanical and electric properties compared to zirconia-based solid electrolyte

Abstract

The mechanical strength and electrical characteristics of 10 mol% gadolinium (Gd)-doped ceria (10GDC) and gadolinium-samarium (Gd–Sm) co-doped ceria ceramics treated by contact reduction were investigated. The observed increased strength of 10GDC was similar to the strength previously reported for ceria with and without Sm doping. X-ray photoelectron spectroscopy revealed that only the surface was reduced in the strengthened material. In addition, the strengthened ceramic displayed improved hardness at low test loads, which suggested the formation of a surface compression layer. The reducing conditions did not affect the electrical conductivity of the 10GDC material. Co-doping with 10 mol% each of Gd and Sm improved strength and conductivity compared with 10GDC and 20GDC. When the co-doped material was reduced, the electric conductivity remained identical; however, the mechanical strength improved, exceeding the strength of zirconia.