Cation Miscibility and Lithium Mobility in NASICON Li1+xTi2-xScx(PO4)3 (0 ≤ x ≤ 0.5) Series: A Combined NMR and Impedance Study

被引：61

作者：

Kahlaoui, Radhouene ^{[1
]}

Arbi, Kamel ^{[2
,3
]}

Sobrados, Isabel ^{[2
]}

Jimenez, Ricardo ^{[2
]}

Sanz, Jesus ^{[2
]}

Ternane, Riadh ^{[1
]}

机构：

[1] Univ Carthage, Fac Sci Bizerte, Lab Applicat Chim Ressources & Subst Nat & Enviro, Zarzouna 7021, Bizerte, Tunisia

[2] CSIC, ICMM, Madrid 28049, Spain

[3] Delft Univ Technol, Fac Civil Engn & Geosci, Dept Mat & Environm, Microlab, Delft, Netherlands

来源：

INORGANIC CHEMISTRY | 2017年 / 56卷 / 03期

关键词：

SOLID ELECTROLYTES; NEUTRON-DIFFRACTION; IONIC-CONDUCTIVITY; MAS NMR; CONDUCTORS; TRANSITION; NUCLEAR; NA;

D O I：

10.1021/acs.inorgchem.6b02274

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

Rhombohedral NASICON compounds with general formula Li1+xTi2-xScx(PO4)(3) (0 <= x <= 0.5) have been prepared using a conventional solid-state reaction and characterized by X-ray diffraction (XRD), nuclear magnetic resonance (NMR), and impedance spectroscopy. The partial substitution of Ti4+ by Sc3+ and Li+ in pristine LiTi2(PO4)(3) increases unit-cell dimensions and the number of charge carriers. In Sc-rich samples, the analysis of XRD data and Li-6/Li-7, P-31, and Sc-45 MAS NMR spectra confirms the presence of secondary LiScO2 and LiScP2O7 phases that reduce the amount of lithium incorporated in the NASICON phase. In samples with x < 0.3, electrostatic repulsions between Li ions located at M1 and M3 sites increase Li mobility. For x >= 0.3, ionic conductivity decreases because of secondary nonconducting phases formed at grain boundaries of the NASICON particles (core-shell structures). For x = 0.2, high bulk conductivity (2.5 x 10(-3) S.cm(-1)) and low activation energy (E-a = 0.25 eV) measured at room temperature make Li1.2Ti1.8Sc0.2(PO4)(3) one of the best lithium ionic conductors reported in the literature. In this material, the vacancy arrangement enhances Li conductivity.

引用

页码：1216 / 1224

页数：9