Preparation And Properties Of The Li₂O-Al₂O₃-TiO₂-P₂O₅Glass-ceramics And The Thin Films System

Due to its special properties and potential applications, more and more researchers pay attentions to inorganic solid eylectrolyte in recent years. It is the main research direction for solid-state electrolyte to develop inorganic solid electrolytes with high ionic conductivity at room temperature. The preparation and properties of the glass-ceramics and thin films based on LiTi2(PO4)3with NASICON-analogy structure were studied systematicly in this dissertation. The main conclusions are as follows:1. The Li2O-Al2O3-TiO2-P2O5(LATP) glass is poor in ionic conduction, while the conductivity of glass-ceramics prepared by heat treatment increased significantly. The glass-ceramic obtained by heattreated at1000℃of LATP glass shows the total conductivity at25℃coming up to8.6×10-4·cm-1..2. The introduction of SiO2improved glass forming ability, the value of ΔT(Ti-Tg) and KH(Hruby factor) rose from29.9℃and0.04to61.8℃and0.14, respectively. But the glass-ceramic contains much impurity phases, lead to lower ionic conductivity. The ionic conductiviy of glass-ceramic at room temperature comes up to4.1×10-4S·cm-1.3. The introduction of appropriated amount of B2O3results also in the increased glass forming tendency. The activation energy for crystallization reduced and the mode of crystal growth changed from one-dimensional to two dimensional growth. The boron addition promots the precipitation of the main crystalline phase LiTi2(PO4)3, restrains the precipitation of second phase, accordingly greatly enhances the conductive properties. The largest ionic conductivity of glass-ceramic (1.3×10-3·cm-1) at25℃was obtained by crystallization of the boron-incorporated glass sheet at900℃. When the heattreating temperature raise to1000℃, the content of unexpected dielectric phases (TiO2, AIPO4) increased, the synergy effects of blocking and space-charge induce the Arrhenius plots exhibiting nonlinear variation.4. La incorporation in LATP could also improve the glass-forming ability; yet La2O3acts as a nucleating agent and promotes the crystallization of AIPO4, TiO2and unknown phases, resulting in the decline of the ionic conductivity.5. LATP amorphous thin films were fabricated at various substrates temperatures from25to400℃by RF magnetron sputtering method using Li1.3Al0.3Ti1.7(PO4)3ceramic target. When the sputtering power is100W and partial pressure of oxygen is20%, with increasing substrate temperature, the thin film structure become denser, smoother and more uniform, the ionic conductivity enhances gradually from0.34×10-5S·cm-1to2.46×10-5S-cm-1. When the substrate temperature is higher than400℃, the reaction between the thin film and ITO glass substrate degrades the conductive performance of thin films.