Non-fluorinated non-solvating cosolvent enabling superior performance of lithium metal negative electrode battery

Abstract Lithium–ion solvation governs the performance of lithium metal anode (LMA) by tuning its interfacial stability. Solvation degree is modulated by adopting fluorinated non-solvating cosolvents (FNSC) to induce anion-rich solvation structure which is beneficial in constructing mechanically stable interface to suppress lithium dendrite. However, FNSC exhibits low cathodic stability owing to their low lowest unoccupied molecular orbital (LUMO) level, aggravating long-term cycling of LMA. We establish that spectroscopically measured Lewis basicity and polarity are critical parameters for designing optimal non-solvating cosolvents. Non-fluorinated non-solvating cosolvents (NFNSC) proposed by our design rule (i.e. anisole, ethoxybenzene and furan) delivered 99.0 % coulombic efficiency over 1400 cycles. In these molecules, the aromatic ring delocalizes oxygen electron pairs and lowers so…