Rechargeable batteries based on sodium metal anodes (SMAs) are endowed with much higher energy density than traditional sodium-ion batteries. However, the use of SMAs brings intrinsic challenges of dendrite growth and unstable solid/electrolyte interphase (SEI) formation. This situation can be further exacerbated at high temperature (>55 °C, HT). Here, we resolve such “HT-challenge” by formulating a thermally stable sulfolane (SL)-based electrolyte that regulates the electrode/electrolyte interfacial chemistries. Besides rapid Na anode passivation enabled by fluoroethylene carbonate (FEC) molecules, a nitrile-based 1,3,6-hexanetricarbonitrile (HTCN) cosolvent is simultaneously introduced, whose three electron-rich -C≡ N groups interact with the electropositive metal ions of Na₃V₂(PO₄)₂O₂F, shielding away solvent attacks occurring at the cathode interface. As a result, we realize a high capacity retention (91.7% after 500 cycles at 1 C) for the Na/Na₃V₂(PO₄)₂O₂F cell at 60 °C, with a high average carbon equivalent (CE) of ∼99.6%. Even at 80 °C, the cell still delivers ∼89.1% of its initial capacity after 100 cycles, whereas the control sample fails rapidly within 30 cycles.

中文翻译：

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通过调节电解质/电极界面化学走向高温金属钠电池

基于钠金属阳极 (SMA) 的可充电电池具有比传统钠离子电池高得多的能量密度。然而，SMA 的使用带来了枝晶生长和不稳定的固体/电解质界面 (SEI) 形成的内在挑战。这种情况在高温 (>55 °C, HT) 时会进一步恶化。在这里，我们通过配制调节电极/电解质界面化学的热稳定环丁砜 (SL) 基电解质解决了这种“HT 挑战”。除了通过氟代碳酸亚乙酯 (FEC) 分子实现快速钠阳极钝化外，同时引入了腈基 1,3,6-己三腈 (HTCN) 助溶剂，其三个富电子-C≡ N 基团与正极金属离子相互作用钠₃ V ₂ (PO₄ ) ₂ O ₂ F，屏蔽在阴极界面处发生的溶剂侵蚀。因此，我们实现了 Na/Na ₃ V ₂ (PO ₄ ) ₂ O ₂ F 电池在 60 °C 下的高容量保持率（在 1 C 下循环 500 次后为 91.7%），具有高平均碳当量（CE ) 约为 99.6%。即使在 80 °C 下，电池在 100 次循环后仍能提供 89.1% 的初始容量，而对照样品在 30 次循环内迅速失效。