In Situ and Operando Characterization of Water-Mediated Ion Intercalation in Transition Metal Oxides

Understanding host-guest interactions of layered inorganic solids ushered in the modern era of portable electronics powered by lithium-ion batteries. Future improvements in the power capability of these devices, and their potential use in emerging technologies such as water treatment, critical element recovery, and ion-based electronics, depend on the development and understanding of new ion insertion hosts with fast insertion kinetics. One avenue is via tuning the interlayer environment of a layered material, since many are flexible hosts whose interlayers can accommodate not just electrolyte ions but also solvents, organic molecules, polymers, and organometallics. In this presentation, I will present our group’s research in the mechanistic understanding of water-mediated ion intercalation in transition metal oxides. I will discuss the role of ordered and confined water networks in transition metal oxide hydrates, the design of metastable hydrated oxides via displacement of interlayer ions by water, and the role of disordered and confined water networks in electrochemical capacitor materials. The fundamental understanding of these materials, which blur the distinction between solid and liquid, paves the way for electrochemical ion insertion applications with high power capability.