Ether‐Anchored MOFs Enable Stable Pseudosuspension Electrolytes for High‐Energy Lithium Metal Batteries

Rational electrolyte design, capable of simultaneously accelerating bulk ion transport and stabilizing interfacial chemistry, is indispensable for achieving high-energy-density lithium metal batteries (LMBs). Here, we demonstrate that short-chain ether-functionalized metal-organic frameworks (S@MOFs) meet these requirements by efficiently tailoring Li⁺ coordination and reconstructing the electrode/electrolyte interphase, achieving durable interfacial ion transport kinetics. Synergistic experimental and theoretical investigations demonstrate that the S@MOF-based electrolyte features distinctive pseudosuspension characteristics, harnessing ether chemistry that affords Li-metal compatibility and Li-salt coordination in concert with MOF's abundant binding sites and ordered rigid frameworks. The resultant S@MOF-based electrolyte delivers robust thermodynamic stability across -10 to 60 °C, even in LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811)||Li full-cell configurations. Under lean-electrolyte and 50 µm-thick Li-metal configurations, it achieves 92.40% capacity retention for LiCoO₂||Li after 1000 cycles. Remarkably, 90.70% for quasi-solid-state NCM811||Li (500 cycles), and 93.21% for Na₃V₂(PO₄)₃||Na (3000 cycles) were obtained, confirming its broad applicability across alkali-metal battery chemistries.