Li metal is considered an ideal anode material for high-energy-density rechargeable Li metal batteries (LMBs). Nevertheless, sluggish Li⁺ transport kinetics and uncontrolled Li dendrite growth result in poor cycling performance, impeding its practical application. In this study, MgF₂-infiltrated UiO-66 nanoparticles (I-MgF₂@UiO) with F-terminated groups are developed as artificial protective layers for Li metal anodes. The fluorination of UiO-66-based metal–organic framework nanoparticles modifies their nanopores to allow the permeation of MgF₂. The F-terminated groups and infiltrated MgF₂ in the I-MgF₂@UiO electrode effectively facilitate the dissociation of the lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt and the desolvation of the solvated Li⁺ clusters, resulting in fast Li⁺ transport kinetics with a high Li⁺ transference number and ionic conductivity. Furthermore, lithiophilic Mg_xLi_y alloys and LiF-rich solid electrolyte interphase (SEI) that form on the Li metal during the Li plating/stripping process provide a homogeneous Li⁺ flux and suppress Li dendritic growth. Benefiting from the I-MgF₂@UiO artificial layer, full cells coupled with a LiFePO₄ cathode show a long lifespan of over 2000 cycles even at a high current rate of 10C. The findings provide new insights and a promising strategy for the practical application of high-energy-density LMBs.

中文翻译：

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用于无枝晶锂金属电池的氟化镁工程 UiO-66 人工保护层


锂金属被认为是高能量密度可充电锂金属电池（LMB）的理想负极材料。然而，缓慢的锂 ⁺ 传输动力学和不受控制的锂枝晶生长导致循环性能不佳，阻碍了其实际应用。在本研究中，开发了具有F封端基团的MgF ₂ 渗透的UiO-66纳米颗粒（I-MgF ₂ @UiO）作为锂金属负极的人工保护层。 UiO-66 基金属有机骨架纳米颗粒的氟化修饰了其纳米孔，以允许 MgF ₂ 渗透。 I-MgF ₂ @UiO 电极中的 F 封端基团和渗透的 MgF ₂ 有效促进了双(三氟甲磺酰基)亚胺锂 (LiTFSI) 盐的解离和去溶剂化。溶剂化的 Li ⁺ 簇，导致快速的 Li ⁺ 传输动力学，具有高 Li ⁺ 迁移数和离子电导率。此外，在镀锂/剥离过程中在锂金属上形成的亲锂镁 _x Li _y 合金和富含 LiF 的固体电解质中间相 (SEI) 提供了均匀的 Li ⁺ 通量并抑制锂枝晶生长。受益于 I-MgF ₂ @UiO 人造层，与 LiFePO ₄ 阴极结合的全电池即使在 10C 的高电流倍率下也表现出超过 2000 次循环的长寿命。这些发现为高能量密度 LMB 的实际应用提供了新的见解和有前景的策略。