The rise of metal-organic frameworks for electrolyte applications

Metal-organic frameworks (MOFs) have been attracting great attention for application in electrolytes. Benefiting from the controllable chemical composition, tunable pore structure and surface functionality, MOFs offer great opportunities for synthesizing high-designability and high-performance electrolytes. This review emphasizes the state-of-the-art progress of MOF-derived electrolytes, including MOF-based solid-state electrolytes (SSEs,i.e., ionic liquid-based SSEs, polyoxyethylene (PEO)-based SSEs, single-ion conducting SSEs and others) and MOF-modified liquid electrolytes (i.e., self-assembling free-standing MOF separators, MOF-based composite separators and MOF membranes as coating interlayers on electrodes). A comprehensive discussion of fundamental chemistry including the structure characteristics, fabrication challenges and ion transfer mechanism is provided first. Next, the advances and challenges in various categories of MOF-derived electrolytes are summarized in detail. Finally, the opportunities and directions for future research of MOF-derived electrolytes are also proposed. This review will deepen the understanding about MOF-derived electrolytes and promote the development of high-performance batteries.