Microstructure and Conductivity of Electric Field-Assisted Pressureless Sintered Li 7 La 3 Zr 1.9 Ta 0.1 O 12 Solid Electrolytes

Green compacts of Li7La3Zr1.9Ta0.1O12 ceramic powders, synthesized by solid state reaction, were sintered by applying electric fields at 590 oC and 670 oC during 5 min. Thickness shrinkage, electric voltage and current were monitored simultaneously. The electrical resistivity of the sintered pellets was evaluated by the impedance spectroscopy technique. Even though Li7La3Zr1.9Ta0.1O12 solid electrolytes may be sintered at temperatures and times lower than those used in conventional sintering, X-ray diffraction analyses showed non-homogeneous distribution of structural phases, with cubic phase in the bulk and tetragonal phase at the pellet surfaces.