An Ion‐Channel‐Restructured Zwitterionic Covalent Organic Framework Solid Electrolyte for All‐Solid‐State Lithium‐Metal Batteries

Abstract

AbstractOrganic solid electrolytes offer an effective route for safe and high‐energy‐density all‐solid‐state Li metal batteries. However, it remains a challenge to devise a new strategy to promote the dissociation of strong ion pairs and the transport of ionic components in organic solid electrolytes. Herein, a zwitterionic covalent organic framework (Zwitt‐COF) with well‐defined chemical and pore structures is prepared as a solid electrolyte capable of accelerating the dissociation and transport of Li ions. The Zwitt‐COF solid electrolyte exhibits a high room‐temperature ionic conductivity of 1.65 × 10−4 S cm−1 with a wide electrochemical stability window. Besides, the Zwitt‐COF solid electrolyte displays stable Li plating/stripping behavior via effective inhibition of the formation of Li dendrites and dead Li, leading to superior long‐term cycle performance with retention of 99% discharge capacity and 98% Coulombic efficiency in an all‐solid‐state Li‐metal battery. Theoretical simulations reveal that the incorporation of zwitterionic groups into COF can facilitate the dissociation of strong ion pairs and reconstruct the AA‐stacking configuration by dissociative adsorption of Li+ ions on Zwitt‐COF producing linear hexagonal ion channels in the Zwitt‐COF solid electrolyte. This strategy based on Zwitt‐COF can provide an alternative way to construct various solid‐state Li batteries.