Fabrication and electrical properties of Si-based La10−xBix(SiO4)6O3 apatite ionic conductor

In this paper we report an investigation about the relationship between Bi content and conductivity for the La10−xBix(SiO4)6O3 (x = 0.5–2) specimens. Increasing Bi content in apatite-type La10−xBix(SiO4)6O3 specimen leads to increasing the average grain size and sinterability because some Bi ion deposited at grain boundaries which promotes grain growth. The relative sintered density of the La8Bi2(SiO4)6O3 specimen is 98%. There is a small shift in diffraction angle of XRD peaks, complicated lattice distortion was observed in the X-ray pattern with increasing content of Bi. Electrical conductivity of La10−xBix(SiO4)6O3 specimen increased with increasing Bi contents and the value of the La8Bi2(SiO4)6O3 specimen is 2.4 × 10−4 S cm−1 at 700 °C.