Lithium lanthanum titanium oxide solid-state electrolyte by spark plasma sintering

Inorganic lithium solid-state electrolytes with advantage of safety are considered as the candidates to substitute the organic liquid electrolytes in lithium ion batteries. Sintering of these solid electrolytes always requires high-temperature and long time. In this paper, spark plasma sintering was employed to prepare lithium lanthanum titanium oxide solid-state electrolyte. X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy were preformed to characterize their microstructure and ionic conductivity. The results showed that fine-grained electrolytes with high relative density of about 98.5% were obtained by sintering the oxide ceramics at 1050 deg. C for only 3 min. The ionic conductivity increases as the ceramic density increases. Grain boundaries in oxide ceramics dominate the Li+ transport.