Syntheses, Crystal Structures and Properties of Lithium Aluminum Titanium Phosphates

• Main Authors: Chien-Ying Chen, 陳建穎
• Other Authors: 李光華
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/97481443339236366797

碩士 === 國立中央大學 === 化學學系 === 104 === 　　Three lithium aluminum titanium phosphates, Li2+xAl1.18Ti0.82(PO4)3 (A1), Li1+xAlxTi2-x(PO4)3 (A2) and Li1.5Al0.5Ti1.5(PO4)3 (A3) were synthesized by the high-temperature, high-pressure hydrothermal method and sol-gel method. A1 were structurally characterized by powder and single X-ray diffraction, A2 and A3 were structurally characterized by powder X-ray diffraction. These compounds were further characterized by TXRF, EDS and 7Li NMR. A2 and A3 were analyzed for electrochemical properties. 　　Compound A1, A2 and A3 all consist of MO6 octahedral which are corner-shared with [PO4] tetrahedral. Two MO6 octahedra and three [PO4] tetrahedra are connected to form a lantern unit. Compound A1 has an anti-NASICON structure in which the lantern units are connected in an anti-parallel way. The Li+ cations are located at sites in the six-membered rings. Compound A2 and A3 both adopt the NASICON structure in which the lantern units are connected in a parallel way. The Li+ cations are located at sites in the eight-membered rings. Compound A3 shows a bulk conductivity of 8.7 × 10-4 S·cm-1. Microcontact impedance study on a single of A2 shows a very good conductivity of 7.07 × 10-3 S·cm-1 which is comparable to that of the liquid electrolyte LA25.