Influence of lanthanum additive on phase transition, microstructure and lithium ionic conductivity of beta-eucryptite

摘要

Lanthanum (La) has been used for the first time as an additive in the sol-gel precursor lithium aluminosilicate (Li_2O-Al_2O_3-2SiO_2) to prepare β-eucryptite at different temperatures. The influence of La additive on the phase transition of β-eucryptite was studied by X-ray diffraction and differential scanning calorimetry. Scanning electron microscope analysis showed that plenty of large aspect ratio rod-like β-eucryptite was formed in the sample containing La additive at 1180℃, and then gradually disappeared at higher sintering temperature. The La additive formed a low-temperature liquid phase LiLaSiO_4 and promoted the crystal growth of β-eucryptite at 1350 ℃. Li~+ conductivity of bulk β-eucryptite with La additive was higher than that without La additive below 603 K.