Lithium Mobility in Li_1.2Ti_1.8M_0.2(PO₄)₃ Compounds (M: Al, Ga, Sc, In) as Followed by NMR and Impedance Spectroscopy.

Abstract

Compounds (M: Al, Ga, Sc, In) as Followed by NMR and Impedance Spectroscopy. -As revealed by XRD, NMR, and impedance spectroscopy most of the trivalent cations of the title compounds are incorporated into the NASICON structure, increasing the amount of mobile lithium ions. Analysis of the quadrupole constant and spin-spin relaxation rate deduced from 7 Li NMR spectra of the Al-containing compound indicate the existence of two regimes associated with local and long-range motion of Li. At increasing temperature, correlated motions decrease, reducing activation energy of lithium motion. -(ARBI, K.; LAZARRAGA, M. G.; BEN HASSEN CHEHIMI, D.; AYADI-TRABELSI, M.; ROJO, J. M.; SANZ*, J.; Chem.

Local structure and lithium mobility in intercalated Li3AlxTi2−x(PO4)3 NASICON type materials: a combined neutron diffraction and NMR study

“…Pristine Li 1+x Al x Ti 2Àx (PO 4 ) 3 samples, with x = 0 and 0.2, were prepared by heating stoichiometric mixtures of Li 2 CO 3 , (NH 4 ) 2 HPO 4 , Al 2 O 3 and TiO 2 in the interval 573-1373 K, following the procedure described previously. 24,29,30 Lithium intercalated Li 3 Ti 2Àx Al x (PO 4 ) samples were prepared by chemical lithium insertion; for that, n-butyl-lithium was added under stirring to pristine Li 1+x Al x Ti 2Àx (PO 4 ) 3 samples dispersed in hexane. 31 The product was washed with dry hexane and finally dried under vacuum.…”

Insight into Design of Improved Oxide Ion Conductors: Dynamics and Conduction Mechanisms in the Bi0.913V0.087O1.587 Solid Electrolyte

“…7 This level of difference between the activation energies determined from the impedance measurements and measurements such as QENS, solid state NMR, and tracer diffusion measurements, as well as simulations, has been reported in a range of fast ion conductors, e.g., for nominally "Na-doped SrSiO 3 ", 31 La 2 Mo 2 O 9 , 16 and other oxide ion conductors, 32,33 as well as Na + ion conductors 34,35 and Li + ion conductors. 36,37 Recent studies ascribed this discrepancy between macroscopic and microscopic diffusion to the fact that the activation energy for the former can be affected by ion−ion interaction, while the energy barriers from QENS and simulations correspond to independent oxygen hops. 38,39 Oxide Ion Dynamics and Conduction Mechanisms Investigated by Ab Initio Molecular Dynamics.…”

Electrospun Sn-doped LiTi2(PO4)3/C nanofibers for ultra-fast charging and discharging

“…The preferential occupancy of M 1 sites by lithium for LiTi 2 (PO 4 ) 3 has been observed from neutron diffraction experiments. 21 Although Li ions in the as-prepared lithium titanium phosphates mainly occupy the M 1 sites, obvious lithium disorders between M 1 and M 2 sites occur (see Table 2). For both LiTi 2 (PO 4 ) 3 /C and LiTi 1.8 Sn 0.2 (PO 4 ) 3 /C, the occupancy of Li in M 1 sites is 0.7886, and the Li occupancy in M 2 sites is 0.0777.…”