Synthesis and electrical properties of scheelite Ca1−xSmxMoO4+δ solid electrolyte ceramics

Scheelite-type Ca1−xSmxMoO4+δ electrolyte powders were prepared by the sol–gel auto-combustion process. The crystal structure of the samples was determined by employing the techniques of X-ray diffraction (XRD). According to the XRD analysis, the formed continuous series of Ca1−xSmxMoO4+δ (0 ≤ x ≤ 0.3) solid solutions had the structure of tetragonal scheelite, and the lattice parameters increased with increasing x in the Sm-substituted system. Results of sinterability and electrochemical testing revealed that the performances of Sm-doped calcium molybdate were superior to that of pure CaMoO4. Ca1−xSmxMoO4+δ ceramics show higher sinterability, and the Ca0.8Sm0.2MoO4+δ sample with 98.7% of the theoretical density were obtained after being sintered at 1250 °C for 4 h. The conductivity increased with increasing samarium content, and a total conductivity 9.54 × 10−3 S cm−1 at 800 °C could be obtained in Ca0.8Sm0.2MoO4+δ sintered at 1250 °C for 4 h.