Physical Mechanisms of Improved Performance of Scaffolded Zinc-Silver Battery Cathodes

Nanostructuring can greatly improve the electrode stability of rechargeable battery systems, such as Zn-Ag. In this report, we investigate the physical mechanisms by which nanostructuring alters structural properties of nanomaterials and thereby influences the structural stability of electrodes. We specifically consider the effects of Au-based nanoscaffolds on Ag. Through density functional theory calculations, we propose that the charge transfer at the Au-Ag interface can facilitate the formation of Ag₂O from Ag centers. Structural analysis of samples prepared in this work shows that Ag₂O is extruded from Au-Ag material in the form of sheets. Interestingly, the length scale of such protrusions depends on the Au mole fraction that significantly alters the system's overall structural morphology. We rationalize these findings via kinetic Monte Carlo simulations of the Ag₂O growth process and highlight the role of Au as a heterogeneous nucleation center.