High power and energy density, long cyclability, and tolerance for wide temperature (seasonal and daily operational temperature differences) must be considered to construct large‐scale sodium secondary batteries. In this regard, Na₃V₂(PO₄)₂F₃ (NVPF) has become a subject of interest as a high‐performance positive electrode material owing to its high energy density. However, the high operating voltage of NVPF causes continuous decomposition of electrolytes during cycles, resulting in significant capacity fading and low Coulombic efficiency. In this study, the electrochemical performance of the NVPF electrode in organic solvent electrolytes with and without additives and an ionic liquid is investigated at high voltage regimes over a wide temperature range (−20 °C to 90 °C). The results reveal that the performance of organic electrolytes is still insufficient even with additives, and the ionic liquid electrolyte demonstrates high electrochemical stability and cyclability with NVPF electrodes over a temperature range from −20 °C to 90 °C, achieving stable cycling over 500 cycles. The detailed electrochemical analysis combined with X‐ray photoelectron and energy dispersive X‐ray spectroscopy indicates that a sturdy cathode electrolyte interphase layer around the electrode protects it from capacity fading at high voltage and elevated temperature, resulting in high Coulombic efficiency.

中文翻译：

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耐高压Na3V2（PO4）2F3正极的电解质，可抵抗温度变化

构造大型钠二次电池必须考虑高功率和能量密度，长循环性以及对宽温度的耐受性（季节性和日常工作温度差）。就这一点而言，Na ₃ V ₂（PO ₄）₂ F ₃（NVPF）由于其高能量密度而成为高性能正极材料的关注主题。但是，NVPF的高工作电压会导致电解液在循环过程中不断分解，从而导致容量显着下降和库仑效率低。在这项研究中，研究了NVPF电极在有机溶剂电解质中（无论有无添加剂和离子液体）在宽电压范围（-20°C至90°C）下的电化学性能。结果表明，即使添加了添加剂，有机电解质的性能仍然不足，并且离子液体电解质在-20°C至90°C的温度范围内具有NVPF电极的高电化学稳定性和可循环性，可在500次循环中实现稳定的循环。