Electrochemical and structural evolution of structured V₂O₅ microspheres during Li-ion intercalation

With the development of stable alkali metal anodes, V₂O₅ is gaining traction as a cathode material due to its high theoretical capacity and the ability to intercalate Li, Na and K ions. Herein, we report a method for synthesizing structured orthorhombic V₂O₅ microspheres and investigate Li intercalation/de-intercalation into this material. For industry adoption, the electrochemical behavior of V₂O₅ as well as structural and phase transformation attributing to Li intercalation reaction must be further investigated. Our synthesized V₂O₅ microspheres consisted of small primary particles that were strongly joined together and exhibited good cycle stability and rate capability, triggered by reversible volume change and rapid Li ion diffusion. In addition, the reversibility of phase transformation (α, ε, δ, γ and ω-Li_xV₂O₅) and valence state evolution (5+, 4+, and 3.5+ ) during intercalation/de-intercalation were studied via in-situ X-ray powder diffraction and X-ray absorption near edge structure analyses.