Electrolytes are widely considered as a key component in Li–O₂ batteries (LOBs) because they greatly affect the discharge-charge reaction kinetics and reversibility. Herein, we report that 1,3-dimethyl-2-imidazolidinone (DMI) is an excellent electrolyte solvent for LOBs. Comparing with conventional ether and sulfone based electrolytes, it has higher Li₂O₂ and Li₂CO₃ solubility, which on the one hand depresses cathode passivation during discharge, and on the other hand promotes the liquid-phase redox shuttling during charge, and consequently lowers the overpotential and improves the cyclability of the battery. However, despite the many advantages at the cathode side, DMI is not stable with bare Li anode. Thus, we have developed a pretreatment method to grow a protective artificial solid-state electrolyte interface (SEI) to prevent the unfavorable side-reactions on Li. The SEI film was formed via the reaction between fluorine-rich organic reagents and Li metal. It is composed of highly Li⁺-conducting Li_xBO_y, LiF, Li_xNO_y, Li₃N particles and some organic compounds, in which Li_xBO_y serves as a binder to enhance its mechanical strength. With the protective SEI, the coulombic efficiency of Li plating/stripping in DMI electrolyte increased from 20% to 98.5% and the fixed capacity cycle life of the assembled LOB was elongated to 205 rounds, which was almost fivefold of the cycle life in dimethyl sulfoxide (DMSO) or tetraglyme (TEGDME) based electrolytes. Our work demonstrates that molecular polarity and ionic solvation structure are the primary issues to be considered when designing high performance Li–O₂ battery electrolytes, and cross-linked artificial SEI is effective in improving the anodic stability.

电解质被广泛认为是 Li-O ₂电池 (LOB) 的关键成分，因为它们极大地影响放电-充电反应动力学和可逆性。在此，我们报道 1,3-二甲基-2-咪唑啉酮 (DMI) 是 LOB 的优良电解质溶剂。与传统的醚基和砜基电解质相比，它具有更高的Li ₂ O ₂和Li ₂ CO ₃一方面抑制放电时正极钝化，另一方面促进充电时液相氧化还原穿梭，从而降低过电位，提高电池的循环性能。然而，尽管在正极方面有许多优势，但 DMI 与裸锂负极并不稳定。因此，我们开发了一种预处理方法来生长保护性人造固态电解质界面 (SEI)，以防止对 Li 的不利副反应。SEI膜是通过富氟有机试剂与金属锂反应形成的。由高Li ⁺导电Li _x BO _y , LiF, Li _x NO _y , Li _3组成N 颗粒和一些有机化合物，其中 Li _x BO _y作为粘合剂以增强其机械强度。使用保护性 SEI，DMI 电解液中 Li 沉积/剥离的库仑效率从 20% 提高到 98.5%，组装的 LOB 的固定容量循环寿命延长至 205 次，几乎是二甲基亚砜循环寿命的五倍(DMSO) 或基于四甘醇二甲醚 (TEGDME) 的电解质。我们的工作表明，分子极性和离子溶剂化结构是设计高性能 Li-O ₂电池电解质时要考虑的首要问题，交联人工 SEI 可有效提高阳极稳定性。