Structural modifications of Li_xV₂O₅ in a composite cathode (0≤x < 2) investigated by Raman microspectrometry

Abstract

The structural behaviour of the Li x V 2 O 5 active material in a composite electrode is determined upon lithium insertion/extraction in the 4-2.15 V potential range (0 ≤ x < 2) using Raman microspectrometry. For the first time, a detailed description of phase transitions occurring in the V 2 O 5 composite electrode is provided by Raman spectroscopy, on the basis of a complete assignment of the spectra. This approach has been successful because of the knowledge of the Raman fingerprints of the chemically lithiated compounds, combined with a rigorous and systematic deconvolution of the Raman spectra obtained for the electrochemically lithiated materials. The successive emergence of α, ε, δ and γ phases is clearly established, as well as the α/ε, ε/δ and δ/γ biphasic regions corresponding to the 3.4, 3.2 and 2.3 V potential plateaus, respectively. This study shows that Raman spectroscopy constitutes a sensitive and relevant tool to explore the emergence of the various phases governing the electrochemical properties of cathode materials for lithium batteries.

Understanding the Influence of Polypyrrole Coating over V2O5 Nanofibers on Electrochemical Properties

“…The peaks located at143, 196, 283, 302, 404, 481, 523, 696 and 992 cm -1 can be assigned to the characteristic vibration modes of orthorhombic V 2 O 5, in a good agreement with the previous report 36. Among them, the strongest peak at 143 cm -1 is attributed to the skeleton bent vibration, while the narrow peak at 992 cm -1 corresponds to the stretching vibration of vanadium atoms connected to oxygen atoms through double bonds, which is also a proof of the layered structureof V 2 O 5 .…”

Synthesis of γ-LiV2O5 nanorods as a high-performance cathode for Li ion battery

“…It should be noted that the ω-phase will turn to irreversible rock salt-type structure when x>3. γ-LiV 2 O 5 consists of a puckered layered framework in which Li ions are located between the (VO 5 ) n layers. As one of the promising cathode materials for Li ion battery, it has attracted lots of attention in recent years [18][19][20][21][22][23]. However, there are not too many reports for synthesis of this material because it is very difficult to prepare γ-LiV 2 O 5 , in which there are two valence states (V 5+ and V 4+ ) of vanadium co-existing [20][21][22][23].…”

Electrochemically formed α’-NaV2O5: A new sodium intercalation compound

“…It constitutes a complementary tool to the long range more conventional techniques such as X-Ray diffraction. As a matter of fact, this structural probe has been successfully used to investigate a wide variety of electrode materials [16][17][18][19][20][21][22][23][24][25][26][27][28].…”