Recent progress on metal–organic framework-based separators for quasi-solid-state lithium metal batteries

Although lithium-ion batteries (LIBs) are emerging as one of the leading energy storage technologies due to their high energy density, high specific capacity, and fast charging speed, major challenges remain regarding the use of liquid electrolytes (LEs). These LEs directly affect the safety and durability of the batteries. While alternative materials such as rigid solid-state electrolytes (SSEs) have been developed to improve safety, they often suffer from poor ionic conductivity and inadequate interfacial contact with the electrodes. These issues hinder the production and widespread application of LIBs. To overcome these disadvantages, quasi-solid-state electrolytes (QSSEs), which include both liquid and solid components, have been extensively researched. Among these, metal-organic frameworks (MOFs) with diverse morphological designs and porous structures are considered promising materials for the fabrication of high-performance QSSEs. This review summarizes recent research on MOF-based separators for lithium metal batteries (LMBs), including native MOFs, MOF composites, and MOF derivatives. The fabrication processes and mechanisms for enhancing the electrochemical performance of each separator material are discussed. Furthermore, the prospects of this promising material for LMBs are provided.