Ionic and electronic conductivity in some alkali vanadates

Tuning mobility and stability of lithium ion conductors based on lattice dynamics

“…The activation energy were measured using electrical impedance spectroscopy (EIS) (Fig. S6, ESI †), and are consistent with prior work Li 3 PO 4 (Pnma), 24 Li 3 VO 4 (Pmn2 1 ), 44 8 was taken from previous work. The blue and orange colours refer to the HT phase (space group Pmna) and the LT phase (space group Pmn2 1 ), respectively.…”

“…Measured activation energy of Li 3 PO 4 (Pnma), Li 3 VO 4 (Pmn2 1 ), Li 3.4 Ge 0.4 P 0.6 O 4 (Pnma) and Li 3+x Ge x V 1Àx O 4 (x = 0.2, 0.4, 0.6 and 1) obtained in this study are in agreement with previous EIS measurements. 10,24,44,45 As the measured activation energy of stoichiometric LISICONs consists of both enthalpy of defect formation and enthalpy of migration, such a correlation for stoichiometric LISICONs does not explicitly imply lowered lithium migration barrier with softening of the total phonon band center. We further show that the measured activation energy for 8 substituted LISICONs with partial lithium occupancy, which corresponds largely to lithium ion migration enthalpy, was decreased with softening of the total phonon band center.…”

Structural and Thermochemical Chemisorption of CO2 on Li4+x(Si1–xAlx)O4 and Li4–x(Si1–xVx)O4 Solid Solutions

“…In these samples, the product external shell is composed by Li 2 CO 3 , Li 2 SiO 3 , and Li 3 VO 4 (see reaction ). Additionally, it should be mentioned that Li 3 VO 4 has a slower lithium diffusion coefficient than Li 2 CO 3 and Li 2 SiO 3 . Therefore, the presence of Li 3 VO 4 on the external shell must reduce importantly the CO 2 chemisorption by decreasing the lithium diffusion; in comparison to the pure Li 4 SiO 4 sample, which only contains Li 2 CO 3 and Li 2 SiO 3 on the external shell of products. Li 4 − italicx ( Si 1 − x V x ) normalO 4 + ( 1 − x ) CO 2 → ( 1 − x ) Li 2 CO 3 + ( 1 − x ) Li 2 SiO 3 + italicx normalLi 3 VO 4 …”

Synthesis and Characterization of Na5[VO4][O] and Na4[VO4][OH]

“…As a result the C.N. (Na/O) is partially increased from 4 to 6, which is important for the understanding of the ionic conductivity of the high-temperature phase [8,20].…”