An X-ray Absorption Spectroscopy Study of the Cathodic Discharge of Ag2VO2PO4: Geometric and Electronic Structure Characterization of Intermediate phases and Mechanistic Insights

Bimetallic phosphorus oxides have emerged as attractive candidates for use as cathode materials in the next generation of lithium-based batteries owing to the operation of multielectron transfer processes and thermochemical stabilities conferred by the incorporation of phosphate groups. In particular silver vanadium phosphorus oxide, Ag2VO2PO4, shows a much desired in situ conductivity enhancement upon discharge resulting in inherently high power capability with minimal conductive additives needed. However, the amorphization of Ag2VO2PO4 during electrochemical discharge precludes the use of standard diffraction tools to monitor changes in the local electronic and geometric structure. Here, we have utilized a combination of V K-, V L-, Ag K-, and O K-edge X-ray absorption fine structure spectroscopy to determine the local vanadium and silver oxidation states, local coordination geometry, and stoichiometry for Ag2VO 2PO4 samples with varying extents of electrochemical lithiation. Soft X-ray V L- and O K-edge measurements provide a detailed orbital-specific picture of changes in vanadium electronic structure upon discharge. 2011 American Chemical Society.

Patridge, C. J., Jaye, C., Abtew, T. A., Ravel, B., Fischer, D. A., Marschilok, A. C., ... Banerjee, S.

Patridge, Christopher J||Jaye, Cherno||Abtew, Tesfaye A||Ravel, Bruce||Fischer, Daniel A||Marschilok, Amy C||Zhang, Peihong||Takeuchi, Kenneth J||Takeuchi, Esther S||Banerjee, Sarbajit

An X-ray Absorption Spectroscopy Study of the Cathodic Discharge of Ag2VO2PO4: Geometric and Electronic Structure Characterization of Intermediate phases and Mechanistic Insights Academic Article