(300b) Unravelling Ultrafast Li-Ion Transport in Functionalized Metal-Organic-Framework Based Battery Electrolytes

Non-aqueous fluidic transport and ion solvation properties under nanoscale confinement are poorly understood, especially in ion conduction for energy storage and conversion systems. Herein, metal-organic frameworks (MOFs) and non-protic electrolytes are studied as a robust platform for developing a molecular-level understanding of electrolyte behaviors in confined spaces. By employing computer simulations, along with spectroscopic and electrochemical measurements, we demonstrate several phenomena that deviate from the bulk, including modulated solvent molecular configurations, aggregated solvation structures, and tunable transport mechanisms from quasi-solid to quasi-liquid in functionalized MOF structures. Technologically, taking advantage of these confinement effects may prove useful for addressing stability concerns associated with volatile organic electrolytes while simultaneously endowing ultra-fast transport of solvates, resulting in improved battery performance, even at extreme temperatures. The molecular-level insights presented here further our understanding of structure-property relationships of complex fluids at the nanoscale, information that can be exploited for the predictive design of more efficient electrochemical systems.