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

Abstract Rational electrolyte design, capable of simultaneously accelerating bulk ion transport and stabiliz ing 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 0.8 Co 0.1 Mn 0.1 O 2 (NCM811)||Li full‐cell configurations. Under lean‐electrolyte and 50 µm‐thick Li‐metal configurations, it achieves 92.40% capacity retention for LiCoO 2 ||Li after 1000 cycles. Remarkably, 90.70% for quasi‐solid‐state NCM811||Li (500 cycles), and 93.21% for Na 3 V 2 (PO 4 ) 3 ||Na (3000 cycles) were obtained, confirming its broad applicability across alkali‐metal battery chemistries.