Effect of sintering atmosphere on ionic conduction and structure of Li0.5La0.5TiO3 solid electrolytes

The lattice structure and ionic conductivity in the temperature range from 303 to 383 K for lithium lanthanum titanate Li0.5La0.5TiO3 (LLTO) solid electrolyte sintered in different atmospheres were investigated. All the LLTO ceramics sintered in different atmospheres exhibit a tetragonal structure with the local expansion of the crystal lattice. Conductivity measurement suggests that the formation of Ti3+ promotes the grain conductivity enhancement in LLTO ceramics sintered in nitrogen atmosphere, however, its total conductivity is the lowest compared with those in oxygen and air atmosphere. The ionic conduction behavior in LLTO was discussed on the basis of the local lattice distortion and lithium content. The results show that lithium ion concentration plays a key role in improving the ionic conductivity for LLTO.