Covalent Organic Framework with Multi‐Cationic Molecular Chains for Gate Mechanism Controlled Superionic Conduction in All‐Solid‐State Batteries

Abstract Although solid‐state batteries (SSBs) are high potential in achieving better safety and higher energy density, current solid‐state electrolytes (SSEs) cannot fully satisfy the complicated requirements of SSBs. Herein, a covalent organic framework (COF) with multi‐cationic molecular chains (COF‐MCMC) was developed as an efficient SSE. The MCMCs chemically anchored on COF channels were generated by nano‐confined copolymerization of cationic ionic liquid monomers, which can function as Li + selective gates. The coulombic interaction between MCMCs and anions leads to easier dissociation of Li + from coordinated states, and thus Li + transport is accelerated. While the movement of anions is restrained due to the charge interaction, resulting in a high Li + conductivity of 4.9×10 −4 S cm −1 and Li + transference number of 0.71 at 30 °C. The SSBs with COF‐MCMC demonstrate an excellent specific energy density of 403.4 Wh kg −1 with high cathode loading and limited Li metal source.