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

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.