Operating a Ni-rich cathode beyond 4.3 V safely holds promise for boosting the energy density in lithium-ion batteries (LIBs). Methyl 2,2,2-trifluoroethyl carbonate (FEMC) shows oxidative stability and high safety but suffers from degraded LUMO energy levels once coordinated with Li⁺ within electrolytes. Here, we utilize propylene carbonate (PC) as a functional dopant, which deliberately tunes the FEMC-dominated solvation chemistry and improves LUMO energy levels by dipole–dipole interaction and microsolvating competition. As a result, the optimized electrolyte demonstrates an expanded electrochemical window (4.7 V for NCM811), fire resistance, and a wide liquid range (−60–120 °C), affording 75.6% capacity retention in 1.2 Ah NCM811/graphite pouch cells over 1200 cycles. This “doping strategy” is generalized to other electrolytes (e.g., carbonates, fluorinated esters, and carboxylic esters) and qualifies as ameliorated interfacial compatibility, providing insights for designing a high-safety electrolyte in high-energy LIBs.

中文翻译：

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溶剂化结构中的掺杂：使氟化碳酸盐电解质能够用于高压和高安全性锂离子电池

在 4.3 V 以上安全地运行富镍阴极有望提高锂离子电池 (LIB) 的能量密度。碳酸甲基2,2,2-三氟乙酯（FEMC）具有氧化稳定性和高安全性，但一旦与电解质中的Li ⁺配位，LUMO 能级就会降低。在这里，我们利用碳酸丙烯酯 (PC) 作为功能掺杂剂，它有意调整 FEMC 主导的溶剂化化学，并通过偶极-偶极相互作用和微溶剂化竞争提高 LUMO 能级。因此，优化的电解质表现出扩大的电化学窗口（NCM811 为 4.7 V）、耐火性和宽液体范围（−60–120 °C），在 1.2 Ah NCM811/石墨软包电池中提供 75.6% 的容量保持率1200 个周期。这种“掺杂策略”被推广到其他电解质（例如碳酸盐、氟化酯和羧酸酯），并改善了界面相容性，为设计高能锂离子电池中的高安全性电解质提供了见解。