Bilayer Zwitterionic Metal-Organic Framework for Selective All-Solid-State Superionic Conduction in Lithium Metal Batteries.

Solid-state batteries (SSBs) hold immense potential for improved energy density and safety compared to traditional batteries. However, existing solid-state electrolytes (SSEs) face challenges in meeting the complex operational requirements of SSBs. In this study, we introduce a novel approach to address this issue by developing a metal-organic framework (MOF) with customized bilayer zwitterionic nano-channels (MOF-BZN) as high-performance SSEs. The bilayer zwitterionic nano-channels consist of a rigid anionic MOF channel with chemically grafted soft multi-cationic oligomers (MCOs) on the pore wall. This design enables selective superionic conduction, with MCOs restricting the movement of anions while coulombic interaction between MCOs and anionic framework promoting the dissociation of Li + . MOF-BZN exhibits remarkable Li + conductivity (8.76 × 10 -4 S cm -1 ), high Li + transference number (0.75), and a wide electrochemical window of up to 4.9 V at 30°C. Ultimately, the SSB utilizing flame retarded MOF-BZN achieves an impressive specific energy of 419.6 Wh kg anode+cathode+electrolyte -1 under constrained conditions of high cathode loading (20.1 mg cm -2 ) and limited lithium metal source. The constructed bilayer zwitterionic MOFs presents a pioneering strategy for developing advanced SSEs for highly efficient SSBs. This article is protected by copyright. All rights reserved.