The use of sodium metal as an anode presents a promising avenue for high energy density sodium rechargeable batteries given its high specific capacity and low redox potential. However, sodium metal batteries (SMBs) encounter significant challenges, including interfacial parasitic reactions and dendrite growth. Developing a robust solid electrolyte interphase (SEI) is crucial for SMB engineering. This study introduces hydrofluoroether as a diluent in high-concentration electrolytes, effectively modifying the solvation structure to enhance ion-pair coordination, which leads to an inorganic-rich SEI, mitigating sodium depletion and dendrite formation. Consequently, localized high concentration electrolytes achieve a 98.3% Coulombic efficiency in Na||Cu batteries, while the Na||NaFe_1/3Ni_1/3Mn_1/3O₂ battery retains 86.4% capacity after 750 cycles at 1C. Additionally, the Na||Na₃V₂(PO₄)₃ battery achieves an exceptional average Coulombic efficiency of 99.97% at 1C, with a capacity retention of 95.4% after 517 days. This study provides a framework for enhancing efficiency and longevity in SMBs that can be applied to other battery systems.

中文翻译：

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调节溶剂化壳以加强阴离子-阳离子配位，以增强钠金属电池的稳定性


鉴于其高比容量和低氧化还原电位，使用钠金属作为阳极为高能量密度钠充电电池提供了一条有前途的途径。然而，钠金属电池 （SMB） 面临重大挑战，包括界面寄生反应和枝晶生长。开发稳健的固体电解质界面 （SEI） 对于 SMB 工程至关重要。本研究引入了氢氟醚作为高浓度电解质中的稀释剂，有效地改变了溶剂化结构以增强离子对配位，从而产生富含无机物的 SEI，减轻钠消耗和枝晶形成。因此，局部高浓度电解质在 Na||Cu 电池，而 Na||NaFe_1/3Ni_1/3Mn_1/3O₂ 电池在 1C 下循环 750 次后仍可保持 86.4% 的容量。此外，Na||Na₃V₂（PO₄）₃ 电池在 1C 时实现了 99.97% 的优异平均库仑效率，517 天后容量保持率为 95.4%。本研究为提高 SMB 的效率和使用寿命提供了一个框架，可应用于其他电池系统。