Breaking the Li+ Selectivity Barrier through Unconventional Li+ Transport Enabled by One-Dimensional 18-Crown-6 Stacks

As a canonical ionophore for Na⁺ and K⁺ transport, 18-crown-6 has never been exploited for selective Li⁺ conduction. Here, we report a new artificial Li⁺-transporting channel architecture composed of a bis-amidated naphthalene, two variable alkyl linkers, and two crown ether units. Naphthalene-driven π–π stacking, coupled with a one-dimensional intermolecular hydrogen-bonding network, cooperatively enforces the ordered self-assembly of crown ether units to generate a dual-path transmembrane conduit. This system enables unconventional Li⁺ transport, breaking the Li⁺ selectivity barrier and achieving record-high Li⁺/Na⁺ and Li⁺/K⁺ selectivity ratios of 117.9 and 90.0, respectively. Beyond constituting a rare example of a highly Li⁺-selective artificial ion channel, this work establishes an unprecedented supramolecular design paradigm for reprogramming classical Na⁺- or K⁺-transporting ionophores toward noncanonical Li⁺ selectivity, with broad implications for Li⁺ separation membranes, therapeutic platforms, and the fundamental principles governing selective Li⁺ conduction.