Nonaqueous Ion Transport through Nanopores: A Nonlinear Behavior Driven by Enhanced Ion Correlation

Ion transport through nanoconfinements under aqueous conditions has largely relied on geometric engineering, limiting nonlinear transport behavior to sub-nanometer scales. Here, we demonstrate that low-dielectric environments enable pronounced nonlinear ion transport in single-layer MoS₂ nanopores (3-7 nm). Beyond dielectric control, the degree of nonlinearity can be tuned by ion concentration and pore diameter, which diminishes with increasing pore size and vanishes under high dilutions. Systematic experiments across different types of solvent further confirm the universality of this nonaqueous, nanoconfined nonlinear transport. All-atom molecular dynamics simulations reproduce these observations, revealing a voltage-gated overscreening mechanism: under strong electric fields, excess cations accumulate near the negatively charged pore edges, inducing charge inversion and enhancing anion transport. This mechanism accounts for the observed nonlinear current-voltage characteristics and establishes a "dielectric engineering" paradigm for amplifying electrostatic correlations and controlling ion transport in nanoconfined systems, offering new insights for nanofluidic and electrochemical device design.