A MOF vertical array enables continuous ion transport pathways with high throughput

Abstract

Metal–organic frameworks (MOFs) have attracted a great deal of attention as ion conductive materials to design high-performance composite solid electrolytes (CSEs). However, the sluggish Li⁺ transport arising from the physical contact among MOF particles with numerous interfaces results in insufficient ionic conductivity and inhomogeneous Li deposition. Herein, a MOF array-based CSE is rationally proposed by embedding a MOF vertical array with bilayer polymer electrolytes. The MOF vertical array offers not only continuous ion transport pathways with high throughput and the shortest transport distance, but also open metal sites to anchor the anions and homogenize the Li⁺ flux. Moreover, the bilayer polymer structure enhances the interfacial compatibility with the Li-metal anode and high-voltage cathode simultaneously. Consequently, the resulting MOF array CSE enables the stable cycling of a Li‖Li symmetric cell for over 800 h and high-voltage Li‖NCM cell at room temperature. Therefore, this work opens up a new frontier in engineering CSEs with MOF vertical arrays towards high-performance solid-state lithium batteries at room temperature.