Lithium mobility in titanium based Nasicon Li1+xTi2−xAlx(PO4)3 and LiTi2−x Zrx(PO4)3 materials followed by NMR and impedance spectroscopy

✍ Scribed by K. Arbi; J.M. Rojo; J. Sanz

• Book ID: 104022630
• Publisher: Elsevier Science
• Year: 2007
• Tongue: English
• Weight: 229 KB
• Volume: 27
• Category: Article
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2007.02.118

✦ Synopsis

Titanium-based Nasicon-type compounds with formula Li 1+x Ti 2-x Al x (PO 4 ) 3 and LiTi 2-x Zr x (PO 4 ) 3 , have been prepared and studied with X-ray Diffraction (XRD), Nuclear Magnetic Resonance (NMR) and Electric Impedance (EI) techniques. From the analysis of the 7 Li and 31 P NMR spectra, cation distribution and Li mobility have been deduced. The substitution of Ti 4+ by a large Zr 4+ cation expands the unit cell but the grain interior conductivity remains near that of the parent LiTi 2 (PO 4 ) 3 compound. However, substitution of Ti 4+ by a smaller Al 3+ cation reduces the unit cell dimensions of the Nasicon framework, but enhances about three orders of magnitude the conductivity. In Zr doped samples, the expansion of the unit cell destabilizes Li coordination at M 1 sites; however, in Al doped samples, the increment of Li amount enhances Li-Li repulsions. In both cases, creation of vacancies at M 1 sites increases Li mobility.