MOF-Based 3D Ion-Conducting Network Enables High-Voltage All-Solid-State Lithium Metal Batteries at Room Temperature

Metal-organic frameworks (MOFs) with high surface area, tunable porous structure, and versatile functionality hold great prospects for manipulating ion transport and designing high-performance composite solid electrolytes (CSEs). However, the discontinuous ion transport and poor mechanical support arising from the randomly distributed MOF particles lead to insufficient ionic conductivity and inferior mechanical strength. Herein, a highly efficient and robust MOF-based 3D ion conducting network was rationally designed by in situ grown MOF nanocrystals on the 3D polyimide fiber network, where (1) the optimized MOF with appropriate pore sizes and abundant open metal sites can effectively restrict the movement of the anion to homogenize the Li+ flux, (2) the in situ growth of densely packed MOFs builds continuous ion channels to promote the rapid transport of Li+, and (3) the mechanically and chemically robust polyimide network bestows the CSE with superior mechanical strength and high oxidation stability. Consequently, the resulting CSE demonstrates high ionic conductivity, a high Li+ transference number, excellent Li compatibility, a wide potential window, and excellent mechanical robustness, which enables the stable cycling of high-voltage all-solid-state Li-metal batteries at room temperature.