Furnace-cooled (La2/3−1/3pLip)(Mg1/2W1/2)O3 and quenched (La2/3−1/3pLip)(Mg1/2W1/2)O3 were synthesized, and the Li-ion conductivity was investigated. The activation energy was found to decrease with Li content for (La2/3−1/3pLip)(Mg1/2W1/2)O3 and (La2/3−1/3pLip)(Mg1/2W1/2)O3, while the obvious lattice contraction associated with Li content was not observed. For (La2/3−1/3pLip)(Mg1/2W1/2)O3, the ordered arrangement of the A-site ions varied with Li content, and seemed to be responsible for the decrease in activation energy. Structural refinements of (La2/3−1/3pLip)(Mg1/2W1/2)O3 revealed that the covalent character of the W–O bond increased with Li content. It was concluded that the Coulomb repulsion between W and Li ions dominated the activation energy, and that the increase in covalent character of the W–O bond with Li content was the reason for the decrease in activation energy.

The Relationship between Li Ion Conductivity and Crystal Structure for Ordered Perovskite Compounds, (La2/3−1/3pLip)(Mg1/2W1/2)O3 (p = 0.05, 0.11 and 0.14). T.Katsumata, M.Takahata, N.Mochizuki, Y.Inaguma: Solid State Ionics, 2004, 171[3-4], 191-8