Sulfonated Li-MOF empowered room to high-temperature all-solid-state lithium metal battery

In this work, sulfonic-functionalized Zr-type metal-organic framework (UiO-66-SO3H) was synthesized, and UiO-66-SO3Li was further acquired via subsequent lithiation treatment. It was incorporated as a functional filler into polymer matrix to construct high-performance solid composite electrolytes (SCEs). Structural and morphological analysis as well as different electrochemical tests were carried out. Owing to the well-defined porous channels, abundant lithium-ion transport sites, and the effective regulation of polymer crystallinity by the －SO3－ moieties, at 60°C, the optimized SCE-2 (10wt% UiO-66-SO3Li) exhibits a high ionic conductivity of 5.36×10-4 S cm-1 (1.86×10-4 S cm-1 at room temperature), along with a wide electrochemical stability window of 4.7 V, and a lithium-ion transference number (tLi⁺) as high as 0.623. Meanwhile, the Li|SCE-2|LiFePO4 full cell exhibits superior long-cycle stability at both 60℃ and room temperature, as well as excellent rate capability up to 5 C. What’s more, the SCE-2 SCE can also be coupled with high-voltage LiNi0.5Co0.2Mn0.3O2 ‌(NCM) cathodes. This work verifies that sulfonic-modified UiO-66-SO3Li can effectively regulate Li＋ migration, suppress lithium dendrite growth, and enhance interfacial compatibility, offering a viable approach for the design of advanced solid composite electrolytes.