Electrochemical and structural characterization of lithium intercalation and deintercalation in the γ-LiV2O5 bronze

Structural modifications of LixV2O5 in a composite cathode (0≤x < 2) investigated by Raman microspectrometry

“…3(b). For x > 1, the electrochemical lithium insertion is no longer reversible, as illustrated by the appearance during the first charge of a new redox process located at a higher potential around 3.6 V, ascribed to the formation of the metastable γ variety of V 2 O 5 , whose structure is isomorphic to the high-temperature form γ -LiV 2 O 5 [5,8] (Fig. 3(a)).…”

“…Due to the irreversible structural transition from the δ to the γ phase, the deintercalation of γ -Li x V 2 O 5 does not bring back the δ, ε and α phases, but rather lead to a new metastable γ variety of V 2 O 5 which is structurally similar to the γ phase. [5,8] In spite of these numerous studies, the partial capacity decrease of Li x V 2 O 5 observed upon repeated cycling has not yet been attributed to specific irreversible structural evolution in the host material. X-ray, [13 -16] neutron and electron diffraction [17 -19] studies have been extensively carried out for identifying the structural changes in the composite V 2 O 5 electrode.…”

Synthesis and electrochemical properties of nanocrystalline V2O5 flake via a citric acid-assistant sol–gel method

“…4, the redox occurs in many steps: the four reduction peaks are located at 3.31, 3.05, 2.12 and 1.65 V, and the corresponding oxidation peaks around 3.64 and 3.22 V (vs. Li/Li + ), which can be assigned to the successive phase transformations with lithium ions insertion and extraction, viz. [15][16][17][18]. Also, it is found that the reduction peaks and oxidation peaks in the first cycle are incompletely symmetrical, and the peaks are fading and turning indistinct in the latter cycles, which suggest that there are some irreversible phase transformations during the process of lithium ions insertion and extraction [15,16].…”

“…In acidic solution, V(V) is an oxidant, which can partially oxidize C 6 H 8 O 7 , and thus, itself was reduced to V(IV) forming (VO) 2+ ions with gas evolution. Then (VO) 2+ ions reacted with (NH 4 )C 6 H 7 O 7 producing (NH 4 )(VO)C 6 H 5 O 7 [17,18]. The total reaction equation is as follows:…”

Surface analysis of pulsed laser‐deposited V2O5 thin films and their lithium intercalated products studied by Raman spectroscopy

“…20 Numerous studies have been devoted to the Li x V 2 O 5 system, which appears to be a good candidate for use as a positive electrode material for secondary lithium batteries. 21 Owing to its complexity there is a current debate to determine the phase diagram of the Li x V 2 O 5 system. 22 -23 The first domain corresponding to 0 < x < 1 is well established whereas the second part for x > 1 is controversial.…”