Rechargeable zinc (Zn) metal batteries are attractive for use as electrochemical energy storage systems on a global scale because of the low cost, high energy density, inherent safety, and strategic resource security of Zn metal. However, at low temperatures, Zn batteries typically suffer from high electrolyte viscosity and unfavorable ion transport properties. Here, we studied reversible Zn electrodeposition in mixtures of 1-ethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide ([EMIm]TFSI) ionic liquid, γ-butyrolactone (GBL) organic solvent, and Zn(TFSI)₂ zinc salt. The electrolyte mixtures enabled reversible Zn electrodeposition at temperatures as low as −60 °C. An electrolyte composed of 0.1 M Zn(TFSI)₂ in [EMIm]TFSI:GBL with a volume ratio of 1:3 formed a deep eutectic solvent that optimized electrolyte conductivity, viscosity, and the zinc diffusion coefficient. Liquid-state ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy and molecular dynamic (MD) simulations indicate increased formation of contact ion pairs and the reduction of ion aggregates are responsible for the optimal composition.

中文翻译：

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−60 °C 下的可逆锌电沉积使用深共晶电解质用于低温锌金属电池

由于锌金属的低成本、高能量密度、固有安全性和战略资源安全性，可充电锌 (Zn) 金属电池在全球范围内用作电化学储能系统具有吸引力。然而，在低温下，锌电池通常具有高电解质粘度和不利的离子传输性能。在这里，我们研究了 1-乙基-3-甲基-咪唑双（三氟甲基磺酰基）亚胺 ([EMIm]TFSI) 离子液体、γ-丁内酯 (GBL) 有机溶剂和 Zn(TFSI) 2 锌盐混合物中的可逆锌_电沉积. 电解质混合物能够在低至 -60 °C 的温度下实现可逆的 Zn 电沉积。_{由 0.1 M Zn(TFSI) 2}组成的电解质在体积比为 1:3 的 [EMIm]TFSI:GBL 中形成了一种低共熔溶剂，优化了电解质的电导率、粘度和锌扩散系数。液态¹ H 和¹³ C 核磁共振 (NMR) 光谱和分子动力学 (MD) 模拟表明接触离子对的形成增加和离子聚集体的减少是最佳组成的原因。