Transport and structural properties of pure and Cr doped Li3VO4.
This study deals with the effects of 5 and 10% chromium additions on the transport and structural properties of Li3VO4. The Cr substitution is easily obtained without impurity phases and does not affect the room- and high-temperature host crystal structure, as evidenced by X-ray powder diffraction and micro-Raman analysis. The EPR signals are interpreted in terms of quantified amounts of Cr ions in 5+ and 3+ valence states. Suitable 7Li and 51V MAS NMR spectra simulations agree with the EPR results about the relative amount of Cr5+ and Cr3+ ions substituted in V5+ and Li+ sites, respectively. The Cr3+ presence on Li site, also suggested by Raman results and Rietveld refinements, requires Li vacancies to maintain the charge neutrality. The p-type conductivity, suggested by the positive thermoelectric power coefficients, significantly increases by the cation doping up to an order of magnitude.
Massarotti
V
V
Dipartimento di Chimica Fisica M. Rolla dell'Università, viale Taramelli 16, 27100 Pavia, Italy. vincenzo.massarotti@unipv.it
Capsoni
D
D
Bini
M
M
Mustarelli
P
P
Chiodelli
G
G
Azzoni
C B
CB
Galinetto
P
P
Mozzati
M C
MC