Self-Amplified Surface Charging and Partitioning of Ionic Liquids in Nanopores

Room-temperature ionic liquids in nanopores are important for a wide range of emerging applications---consider electrodes in batteries, fuel cells, and supercapacitors, for example. Using a coarse-grained model that captures the essential physics, this study finds that nanopores favor adsorption of small ions even without surface attraction, which differs qualitatively from the situation for aqueous electrolyte solutions. Moreover, the imbalanced distribution of cations and anions inside a pore yields a net surface charge, promoting further enrichment of small ions. This self-amplified ion partitioning may open further avenues of research on such systems.