Synthesis and electrochemical properties of {\text{C}}{{\text{a}}_{{0.9}}}{\text{L}}{{\text{a}}_{{0.1}}}{\text{W}}{{\text{O}}_{{4 + \delta }}} electrolyte for solid oxide fuel cells

\( {\text{C}}{{\text{a}}_{{0.9}}}{\text{L}}{{\text{a}}_{{0.1}}}{\text{W}}{{\text{O}}_{{4 + \delta }}} \) powder was prepared by gel auto-ignition process. According to X-ray diffraction analysis, the resulted \( {\text{C}}{{\text{a}}_{{0.9}}}{\text{L}}{{\text{a}}_{{0.1}}}{\text{W}}{{\text{O}}_{{4 + \delta }}} \) solid solution has tetragonal scheelite structure. Results of electrochemical testing reveal that the performances of La-doped calcium tungstate are superior to that of pure CaWO4, a conductivity of 5.28 × 10−3 S cm−1 at 800 ○C could be obtained in the \( {\text{C}}{{\text{a}}_{{0.9}}}{\text{L}}{{\text{a}}_{{0.1}}}{\text{W}}{{\text{O}}_{{4 + \delta }}} \) compound sintered at 1,200 ○C. The electrical conductivity as a function of oxygen partial pressure and also the electromotive force of oxygen concentration cell are measured to prove the mainly ionic conductivity of the investigated material.