The Regulation of Ion Transport Microenvironment in Micropores to Precisely Construct Porous Polymer Electrolytes for Solid-State Lithium-Metal Batteries.

Porous solid-state polymer electrolytes have emerged as promising candidates for next-generation batteries owing to their superior safety, excellent interfacial compatibility, and efficient ion transport properties. However, systematically tuning the Li solvent microenvironment within the micropores of PIMs (inherent microporous polymers) to significantly enhance Li conduction remains unexplored. Herein, we propose a strategy for performing microenvironmental engineering within microporous channels. By creating interconnected subnanometer-scale ion transport channels within a rigid and twisted PIM backbone, we precisely regulate the Li solvent interactions in the pore microenvironment. This dual optimization enables the porous polymer electrolyte to exhibit an excellent room-temperature ionic conductivity of 1.08 × 10 S cm, a high lithium-ion transference number (0.88), and wide electrochemical window (5.2 V). These superior electrochemical properties allow the assembled Li-Li symmetric battery to achieve stable deposition/plating over 1500 h at 0.1 mA cm. Consequently, the assembled LFP|PIM-CONH|Li delivers an initial discharge specific capacity of 158.2 mAh g at 0.5 and 25 °C, with a capacity retention rate of 93.6% after 400 cycles. More notably, the assembled pouch cells still exhibit a high discharge specific capacity of 139.2 mAh g after folding and cutting under 0.5 C. Moreover, the introduction of our proposed nonflammable PIM-CONH electrolyte represents a significant advancement, facilitating the transition toward the practical implementation of high-safety and high-energy-density solid-state batteries.