How the Environment Encourages the Natural Formation of Hydrated V₂O₅

Abstract

Herein, we report the microscopic and spectroscopic signatures of the hydrated V 2 O 5 phase, prepared from the α-V 2 O 5 powder, which was kept in deionized water inside an airtight glass container for approximately 2.5 years. The experimental results show an evolution of the V 4+ component in V 2p 3/2 core energy level spectra, and a peak corresponding to σ-OH – bond appeared in the valence band spectra in the hydrated V 2 O 5 powder sample due to the water intercalation. Vanadium metal oxide particles were found to be self-nucleated into micro/nanorods after a long period of exposure to an extremely humid environment. The distinct features in the spectra obtained with high-resolution transmission electron microscopy, micro-Raman scattering, and X-ray photoelectron spectroscopy confirmed the presence of structural water molecules for the first time in the long-aged naturally hydrated V 2 O 5 phase.

Interfacial Chemistry in Aqueous Lithium‐Ion Batteries: A Case Study of V2O5 in Dilute Aqueous Electrolytes

“…Clearly, comparing electron micrographs of the sensors, V 2 O 5 aggregates disappear upon contact with the electrolyte (Figure S5, Supporting Information). However, a minor fraction may re-form into a hydrated phase of V 2 O 5 (denoted HP-V 2 O 5 ) (as reported before [32] and discussed below), anticipatedly in the pores of the electrode, hence explaining the remaining fraction (≈40%) of vanadium mass on the sensor. Indeed, upon electrochemical charging of the sensor electrode, virtually no charge capacity associated with Li + insertion into solid V 2 O 5 in voltage region I (< 0.9 V, Figure 2a) is observed, hence supporting the notion that nearly all solid 𝛼-V 2 O 5 dissolved (c.f.…”

Effect of Carbon Nanotubes on the Na+ Intercalation Capacity of Binder Free Mn2V2O7-CNTs Electrode: A Structural Investigation

“…In the V 2p 3/2 core level spectra (Figure 5b), the pristine sample showed the mixed valance states V 4+/5+ at the binding energies of 515.5 and 517.1 eV, while the electrochemically reduced V 3+ state (BE = 512.9 eV, ∆ = 7.7 eV) was observed in cycled MVO-CNTs sample on both points A and B [43]. Furthermore in O 1s core level spectra the BEs at 530.6 and 533.2 eV are assigned to Mn-O (coordinated with V atoms) and -OH chemical bonds respectively [44,45], which is consistent with previous reported Raman scattering results and C 1s core level spectra of pristine sample. The component of MVO phase appeared at BE of 531.4 eV in O 1s core level spectra.…”