Metal-organic frameworks based solid-state electrolytes for high-performance lithium metal batteries

Solid-state electrolytes (SSEs) are considered a key enabler for next-generation lithium metal batteries (LMBs) due to their enhanced safety and potential for high energy density. However, challenges such as low ionic conductivity and poor electrode/electrolyte interfacial compatibility have hindered their practical application. In this context, metal-organic frameworks (MOFs)-a class of porous crystalline materials consisting of metal nodes and organic linkers-have recently emerged as promising candidates for SSEs design, owing to their high surface area, tunable pore environments, and versatile chemical functionality. While MOFs have been extensively reviewed in supercapacitors, Li-S batteries, and as electrode materials, a focused and up-to-date review specifically addressing MOF's role in all-solid-state lithium metal batteries are still missing. This review aims to fill that critical gap by systematically summarizing recent progress in MOF-based SSEs, including structural design strategies, ion transport mechanisms, and MOF-electrode interfacial engineering. Special emphasis will be placed on structure-property relationships, the role of functional groups and metal centers, and emerging hybrid/composite MOF electrolytes. Finally, we discuss current limitations, scaling challenges, and propose future research directions to guide the rational design and integration of MOF-based SSEs in high-performance LMBs systems. This review will provide valuable insights for both material scientists and battery researchers working toward safe and energy-dense solid-state battery technologies. • Summarizes recent advances in MOF-based solid-state electrolytes for lithium batteries. • Highlights pore size, defects, and functional group engineering for Li + transport. • Reviews 2D, core-shell, anionic, and amorphous MOF architectures for SSEs. • Introduces pore-in-pore COF/MOF hybrids and single-ion conducting MOFs. • Discusses challenges in conductivity, interfacial contact, and scale-up strategies.