Electrochemical reduction of an Ag2VO2PO4 particle: dramatic increase of local electronic conductivity

Abstract

Previously, we reported that electrodes containing silver vanadium phosphate (Ag₂VO₂PO₄) powder exhibit a 15 000 fold increase in conductivity after discharge, concurrent with the formation of silver metal. In this study, in order to disentangle the complex nature of electrodes composed of electroactive powders, an electrochemical reduction of individual particles of Ag₂VO₂PO₄ was conducted, to more directly probe the intrinsic materials properties of Ag₂VO₂PO₄. Specifically, individual particle conductivity data from a nanoprobe system combined with SEM and optical imaging results revealed that the depth of discharge within an Ag₂VO₂PO₄ particle is closely linked to the conductivity increase. Notably, the formation of silver metal may affect both inter- and intraparticle conductivity of the Ag₂VO₂PO₄ material.