Nonaqueous sodium-based batteries are ideal candidates for the next generation of electrochemical energy storage devices. However, despite the promising performance at ambient temperature, their low-temperature (e.g., < 0 °C) operation is detrimentally affected by the increase in the electrolyte resistance and solid electrolyte interphase (SEI) instability. Here, to circumvent these issues, we propose specific electrolyte formulations comprising linear and cyclic ether-based solvents and sodium trifluoromethanesulfonate salt that are thermally stable down to −150 °C and enable the formation of a stable SEI at low temperatures. When tested in the Na||Na coin cell configuration, the low-temperature electrolytes enable long-term cycling down to −80 °C. Via ex situ physicochemical (e.g., X-ray photoelectron spectroscopy, cryogenic transmission electron microscopy and atomic force microscopy) electrode measurements and density functional theory calculations, we investigate the mechanisms responsible for efficient low-temperature electrochemical performance. We also report the assembly and testing between −20 °C and −60 °C of full Na||Na₃V₂(PO₄)₃ coin cells. The cell tested at −40 °C shows an initial discharge capacity of 68 mAh g⁻¹ with a capacity retention of approximately 94% after 100 cycles at 22 mA g⁻¹.

非水钠基电池是下一代电化学储能装置的理想候选者。然而，尽管在环境温度下具有良好的性能，但它们的低温（例如，<0°C）操作受到电解质电阻增加和固体电解质界面（SEI）不稳定性的不利影响。在这里，为了规避这些问题，我们提出了特定的电解质配方，包括线性和环状醚基溶剂和三氟甲磺酸钠盐，它们在低至 -150 °C 时具有热稳定性，并能够在低温下形成稳定的 SEI。在 Na||Na 纽扣电池配置中进行测试时，低温电解质可实现低至 -80 °C 的长期循环。通过异位物理化学（例如，X 射线光电子能谱，低温透射电子显微镜和原子力显微镜）电极测量和密度泛函理论计算，我们研究了负责高效低温电化学性能的机制。我们还报告了在 -20 °C 和 -60 °C 之间的全 Na||Na 的组装和测试₃ V ₂ (PO ₄ ) ₃纽扣电池。^{在-40 °C 下测试的电池显示出68 mAh g -1}的初始放电容量，在22 mA g ^-1 100 次循环后容量保持率约为94% 。