Tuning the Ion Transfer Behavior to Approaching Near‐Unity Li ⁺ Transference via Pore Engineering

ABSTRACT Efficient ion transport plays an important role in lots of applications, especially in advancing electrochemical energy storage technologies. In this work, quasi‐solid‐state electrolytes (QSSEs) with continuous and low‐barrier Li ⁺ pathways are created by concurrent tuning of the compact geometric space of sub‐nanometer pores and their chemical functionality. The compact geometric space limits the entry of excess solvent and shortens Li ⁺ migration distances, while electronegative coordination sites strengthen electrostatic interactions and optimize the primary solvation structure, thereby suppressing anion migration. The resulting modified electrolytes exhibit a high ionic conductivity of 2.33 mS cm ⁻¹ and a Li ⁺ transference number of 0.90 at room temperature, concurrently achieving high conductivity and Li ⁺ ‐dominant conduction. When applied in lithium‐metal batteries (LMBs), the electrolyte enables superior rate capability and long‐term cycling stability. This study highlights the potential of sub‐nanometer pore functionalization as a general materials design strategy for developing high‐performance electrolytes, providing a promising direction for next‐generation energy storage systems. Meanwhile, the distinctive ion transport behavior observed in sub‐nanometer confined environments offers new opportunities for a wide range of applications related to ion transport.