Expanding the Design Flexibility of Electrolyte Solvents for Li–O₂ Secondary Batteries by Incorporating Fluorine Groups

The development of chemically stable electrolytes is crucial for lithium–oxygen battery design. However, modifying electrolyte solvents to enhance the specific properties often increases the number of constituent atoms per molecule, potentially reducing the chemical stability by providing more initiation sites for bond cleavage. This study demonstrates that introducing fluorine moieties into amide-based electrolyte solvents mitigates this trade-off while maintaining lower charging voltages over extended cycles. This effect was consistently observed across various amide-based solvents, including diamides. These findings suggest that introducing fluorine moieties can relax constraints related to the number of constituent atoms, thereby increasing the range of molecular designs.