Synthesis and Impedance Spectroscopy of Ga-Doped La9.33(SiO4)6O2 Apatite Oxide Ion Conductor
Apatite materials are interesting alternative solid oxide fuel cell (SOFC) electrolytes because of their open structure including tunnels for the diffusion of oxide ions and their good chemical stability. However, the conductivity was still relative low when it was used as SOFC in the intermediate operating temperature range. So the apatite-type lanthanum silicates/germanates and doping were widely researched for enhancing conductivity recently. This study reports the influence of Ga doping on conductivity of the apatite phase La9.33(SiO4)6O2 according to the formula La9.33+x/3(SiO4)6-x(GaO4)xO2 where 0 x 2. Samples were prepared by a sol-gel process. The conductivities of all compositions have been obtained by impedance spectroscopy analysis. The conductivity enhancement observed for moderate x values and illustrates further influenced by the tetrahedral cation sublattice and the La vacancies in optimizing the conductivity.
Wei Pan and Jianghong Gong
Z. X. Huang et al., "Synthesis and Impedance Spectroscopy of Ga-Doped La9.33(SiO4)6O2 Apatite Oxide Ion Conductor", Key Engineering Materials, Vols. 434-435, pp. 723-726, 2010