Li 2 O‐Integrated Electrodes Enabling Enhanced Adsorption/Defluorination Kinetics Toward LiF‐Rich Interphase for High‐Performance Lithium Metal Batteries

Abstract Regulating interfacial chemistry at lithium (Li) anodes is vital for constructing robust solid‐electrolyte interphase (SEI) and achieving reliable Li metal batteries (LMBs). Herein, an electrode‐based strategy is proposed to regulate adsorption/defluorination kinetics of fluorinated electrolyte species by incorporating mechanochemically generated Li 2 O nanoparticles into the Li/Li 22 Sn 5 composite electrode, thereby constructing a LiF‐rich SEI. This approach fundamentally differs from conventional methods that rely on concentrated salts or complex electrolyte formulations. Spectroscopic characterizations combined with density functional theory simulations confirm that the integrated‐Li 2 O nanoparticles strongly adsorb FEC and PF 6 – anions and promote their spontaneous defluorination, facilitating the preferential formation of LiF within the SEI. This inorganic‐rich interphase homogenizes Li deposition and mitigates electrolyte corrosion even at 60 °C. Consequently, the composite electrode delivers a high average Coulombic efficiency of 99.0% over 50 plating/stripping cycles in carbonate electrolyte at 1 mA cm −2 and 1 mAh cm −2 . Paired with LiCoO 2 cathodes, it achieves outstanding cyclability with 87.0% capacity‐retention at a low negative‐to‐positive ratio of 2:1 and 84.8% capacity‐retention under lean‐electrolyte conditions (20 µL) after 200 cycles over a wide voltage range of 2.8–4.5 V. This work highlights regulating adsorption/defluorination kinetics as an effective route to engineer LiF‐rich SEI and enable high‐performance LMBs.