A saturated solution of 2.3 M sodium bis(fluorosulfonyl)imide in trimethyl iso-butyl phosphonium bis(fluorosulfonyl)imide ionic liquid shows a high conductivity (0.94 mScm⁻¹ at 50 °C), low ion association, and a wide operational temperature window (−71 °C–305 °C) making it a promising electrolyte for sodium battery applications. Cycling with P2- and O3-Na_2/3[Fe_2/3Mn1/3]O₂ cathode display excellent performance at 50 °C outperforming conventional organic solvent based electrolytes in terms of capacities (at C/10) and long term cycle stability (at C/2). Post analysis of the electrolyte shows no measurable changes while the sodium metal anode and the cathode surface shows the presence of electrolyte specific elements after cycling, suggesting the formation of a stabilizing solid electrolyte interface. Additionally, cycling changes the topography and particle morphology of the cathode. Thus, the electrolyte properties and cell performance match or outperform previously reported results with the additional benefit of replacing the hazardous and flammable organic solvent solutions commonly employed.

中文翻译：

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用于P2-和O3-Na2 / 3 [Fe2 / 3Mn1 / 3] O2阴极材料的钠离子电池的小型季烷基双（氟磺酰基）酰亚胺离子液体电解质

2.3 M双（氟磺酰基）酰亚胺钠在三甲基异丁基tri双（氟磺酰基）酰亚胺离子液体中的饱和溶液显示出高电导率（在50°C时为0.94 mScm ^-1），低离子缔合和宽工作温度范围（-71°C–305°C）使其成为钠电池应用中有希望的电解质。用P2-和O3-Na _2/3 [Fe _2/3 Mn1 / 3] O ₂循环在容量（C / 10）和长期循环稳定性（C / 2）方面，阴极在50°C时表现出优于传统有机溶剂的电解质。电解质的后分析显示没有可测量的变化，而钠金属阳极和阴极表面显示出循环后电解质特定元素的存在，表明形成了稳定的固体电解质界面。另外，循环改变了阴极的形貌和颗粒形态。因此，电解质性质和电池性能与先前报道的结果相匹配或优于先前报告的结果，并且具有替代通常使用的危险和易燃有机溶剂溶液的额外好处。