Transport mechanisms underlying ionic conductivity in nanoparticle-based single-ion electrolytes

Improving the ionic conductivity of electrolytes, while maintaining high lithium transference numbers is crucial for reliable and high-performing lithium-ion battery technologies. Nanoparticle-based electrolytes, in which nanoparticles are embedded in ion-conducting solid polymers or liquids, have emerged as a promising platform in this regard. In this work, we introduce a coarse-grained multiscale simulation approach to identify the mechanisms underlying the ion mobilities in nanoparticle-based single-ion conductors and to clarify the influence of key design parameters on conductivity. Our results suggest that for the experimentally studied electrolyte systems, the dominant pathway for cation transport is along the surface of nanoparticles, in the vicinity of nanoparticle-tethered anions. Within this picture, we identify the influence of nanoparticle volume fraction, anion and cation choices, and solvent (host) polarity on the ionic conductivity. Together, our results provide a complete picture for design considerations in single-ion conducting electrolytes based on nanoparticle salts.