In Situ Tomographic Profiling of Ag$_{2}$VP$_{2}$O$_{8}$ Li-Ion Batteries using Energy Dispersive X-ray Diffraction

Bimetallic cathodes for use in Li-ion batteries have been studied in recent years as they may provide multiple electron reduction, yielding both high capacity and high current on discharge. In this study, we investigate the progress of the reaction of Ag$_{2}$VP$_{2}$O$_{8}$ on discharge in a lithium anode cell using in-situ energy dispersive x-ray diffraction at beamline X17B1 at NSLS I. By measuring diffraction patterns in 20 $\mu$m segments through the cathode as a function of depth of discharge we are able to produce tomographic images of discharged cells. After analyzing the resulting spectra, we were able to observe the presence and relative intensity of Ag metal formed in the cathode upon discharge shedding light on the mechanisms limiting performance.