Nanoscale Interfacial Interaction of Polysulfide with Porous Metal Oxides

Abstract

Sulfur is a promising cathode for high energy density lithium-sulfur battery, but plagued by polysulfide dissolution causing loss of active material and detrimental parasitic reactions. In recent years multiple strategies have been employed to address the parasitic reaction of polysulfide species and increase the life cycle of the Li-S battery. One of the main approaches is employing porous materials as internal reservoirs which can absorb/desorb polysulfides during electrochemical cycling and thereby prevent the shuttling process. Despite intensive efforts to design optimal reservoir materials, the progress in this field is dragged by the knowledge gap in terms of molecular level view about polysulfide interaction with host material. We studied the interaction of polysulfide species including highly reactive trisulfide free radicals with porous silica and alumina metal oxide nano-particles The polysulfide interaction with metal centers of nano-particles are analyzed using combined experimental spectroscopic studies (magnetic resonance and X-ray absorption spectroscopy) and density functional theory based computational methods. This work provides molecular level insight about polysulfide reactivity on metal oxide surfaces which can help in understanding the emergent behaviors of hetrogeneous interfaces.