The synthesis of a new ionic liquid (IL), consisting of the symmetric tetra-butyl-phosphonium (P₄₄₄₄⁺) cation and the (nonafluorobutanesulfonyl-trifluoromethanesulfonyl) imide (IM₁₄^–) anion, via a facile and environmentally-friendly aqueous route is reported. The novel P₄₄₄₄IM₁₄ IL demonstrates excellent thermal and electrochemical stability (beyond 6 V vs. Li⁺/Li⁰ (against Ni-foil)) in combination with good near-room temperature conductivity and ionic liquid characteristics, such as non-measurable volatility and exceptional flame-retardant properties. Employed as electrolyte component in Li-metal cells together with the high-voltage, Li_1.2Ni_0.2Mn_0.6O₂ positive electrode material, enables an initial discharge capacity of 264 mA h g^-1 at 12.5 mA g⁻¹ and improved initial Coulombic efficiency. Additionally, the discharge capacity retention is promising (92.3% after 50 cycles and 84.4% after 100 cycles) when compared with using a conventional organic carbonate-based electrolyte (55.5% after 50 cycles). Further development of this ionic liquid electrolyte may facilitate the practical application of Li-metal anodes in high-voltage/high-energy lithium batteries.

一种新的离子液体 (IL)，由对称的四丁基鏻 (P ₄₄₄₄ ⁺ ) 阳离子和（九氟丁磺酰基-三氟甲磺酰基）亚胺 (IM ₁₄ ^– ) 阴离子组成，通过一种简便且环保的水性途径合成被报道。新型 P ₄₄₄₄ IM ₁₄ IL 表现出优异的热和电化学稳定性（超过 6 V vs. Li ⁺ /Li ⁰（针对镍箔）），以及良好的近室温电导率和离子液体特性，例如不可测量挥发性和卓越的阻燃性能。与高电压 Li _1.2一起用作锂金属电池中的电解质组分镍_0.2锰_0.6 ø ₂正极材料，使得能够264毫安ħg的初始放电容量^-1在12.5毫安克^-1和改进的初始库仑效率。此外，与使用传统的有机碳酸盐基电解质（50 次循环后 55.5%）相比，放电容量保持率（50 次循环后 92.3% 和 100 次循环后 84.4%）很有希望。这种离子液体电解质的进一步发展可以促进锂金属负极在高电压/高能锂电池中的实际应用。