Fluorine-incorporated interface enhances cycling stability of lithium metal batteries with Ni-rich NCM cathodes

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>Li metal anodes and Ni-rich layered oxide cathodes with high reversible capacities are promising candidates for the fabrication of high energy density batteries. However, low Coulombic efficiency, safety hazards from likely vertical Li growth, and morphological instability of Ni-rich cathodes hinder the practical applications of these electrodes. Here, we report that fluorinated compounds can be employed as interface modifiers to extend the applicable voltage range of ether-based electrolytes, which have been used specifically so far for lithium metal batteries with charging cut-off voltages lower than 4 V (vs. Li/Li<SUP>+</SUP>). A complementary electrolyte design using both 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether and fluoroethylene carbonate in concentrated ether-based electrolytes significantly improves the capacity retention (99.1%) in a Li|LiNi<SUB>0.8</SUB>Co<SUB>0.1</SUB>Mn<SUB>0.1</SUB>O<SUB>2</SUB> full cell, with a high Coulombic efficiency of 99.98% after 100 cycles at 25 °C. Thus, the modified electrolyte system is promising for addressing the reductive and oxidative decompositions of labile ether-based electrolytes in high energy density Li metal batteries with Ni-rich cathodes.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ether-based electrolyte formulation for 4V-class Li metal batteries is presented. </LI> <LI> FEC and TTE are employed as the electrode–electrolyte interface modifiers. </LI> <LI> Fluorine-enriched interfaces enable high-performance Li metal batteries. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>