Details

Autor(en) / Beteiligte

• Jimenez, R.
• Sobrados, I.
• Martinez, S.
• Criado, M.
• Perea, B.
• Sanz, J.

Titel

Li conductivity in Li1+xTi2-xAlx(PO4)3 (0.3≤ x≤ 0.7) ceramics prepared from sol-gel precursors

Ist Teil von

• Journal of alloys and compounds, 2020-12, Vol.844, p.156051, Article 156051

Ort / Verlag

Lausanne: Elsevier B.V

Erscheinungsjahr

2020

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Li1+xTi2-xAlx (PO4)3 (LTAP) x = 0.3, 0.4, 0.5 and 0.7) compounds, prepared at 800 °C by sol-gel, have been studied by X-ray diffraction, Nuclear Magnetic Resonance, Scanning Electron Microscopy and Impedance Spectroscopy. The increment of lithium enhances Li–Li repulsions, favoring the creation of vacancies at the conduction paths intersection (M1 sites), increasing Li mobility along (… M1-M2-M1 …) channels in NASICON phases. The partial elimination of segregated AlPO4, LiAlP2O7 and LiTiPO5 phases increased Ti, Al solubility in NASICON, improving overall conductivity in ceramics prepared at 950 °C. The maximum of “bulk” conductivity was produced in x = 0.4 sample, as a consequence of the creation of M1 vacancies and allocation of Li in M2 cavities with optimal Li/vacancy distribution. The presence of secondary phases increased grain boundary impedance, shifting maximum of overall conductivity to x = 0.3 compound. Obtained results are compared with those reported previously in LTPA samples prepared by the ceramic route. •Sol-gel method enlarges the solid-solution limit in Li1+xTi2-xAlx (PO4)3.•Stoichiometry of compounds is close to nominal despite formation of secondary phases.•Crystallite conductivity is maximum at x = 0.4, due to optimal Li distribution.•A proposed jump probability model, reproduces the conductivity maximum at x = 0.4.•The 27Al NMR study indicates the non-random distribution of Ti/Al in the structure.