In operando study of orthorhombic V2O5 as positive electrode materials for K-ion batteries

Herein, the electrochemical performance and mechanism of potassium insertion/deinsertion in orthorhombic V2O5 nanoparticles are studied. The electrode displays an initial potassiation/depotassiation capacity 200 mAh g−1/217 g−1 voltage range 1.5–4.0 V vs. K+/K at C/12 rate, suggesting fast kinetics for insertion/deinsertion. However, quickly fades during cycling, reaching 54 31st cycle. Afterwards, slowly increases up to 80 200th storage upon K ions insertion into is elucidated. In operando synchrotron diffraction reveals that first undergoes a solid solution form K0.6V2O5 phase then, further insertion, it coexistence two-phase reaction. During deinsertion, reaction identified together with irreversible process. XAS confirms reduction/oxidation vanadium insertion/extraction some contributions. This consistent results obtained from diffraction, ex situ Raman, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM). Moreover, XPS “cathode electrolyte interphase” (CEI) formation on decomposition CEI film cycling.