The development of room-temperature sodium sulfur batteries is severely constrained by the sluggish solid-solid conversion kinetics of NaS/NaS and the accumulation of “dead NaS/NaS”. Here, we accelerate the conversion kinetics of NaS/NaS as well as reduce the accumulation of “dead NaS/NaS” by 1-butyl-1-methylpyrrolidine trifluoromethanesulfonate ([P14][OTf]) ionic liquid additive that is compatible with metallic Na and has high NaS/NaS solubility. The results of three-electrode kinetics tests show a significant enhancement of the apparent redox kinetics of NaS/NaS through increasing its concentration. During battery cycling, the increase in NaS/NaS concentration can induce the formation of three-dimensional NaS deposition and reduce the coverage of the electrode effective electroactive area, thus decreasing the battery polarization, especially at high rates. In addition, high NaS/NaS solubility can promote the reuse of “dead NaS/NaS” and greatly improve the utilization of active material. At 2C rate, 351 mAh g can be maintained after 800 cycles, and the capacity decay per cycle is 0.046 %. The rate and cycle performance of the battery are greatly improved. Further, a mechanism is proposed for the enhancement of battery performance via overpotential and diffusion theories.

中文翻译：

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通过具有高 Na2S/Na2S2 溶解度的电解质添加剂加速高性能室温钠硫电池的 Na2S/Na2S2 转化动力学

室温钠硫电池的发展受到NaS/NaS缓慢的固-固转化动力学和“死NaS/NaS”积累的严重制约。在这里，我们通过与金属Na相容的1-丁基-1-甲基吡咯烷三氟甲磺酸盐（[P14][OTf]）离子液体添加剂加速了NaS/NaS的转化动力学，并减少了“死NaS/NaS”的积累且具有较高的NaS/NaS溶解度。三电极动力学测试结果表明，通过增加NaS/NaS的浓度，其表观氧化还原动力学显着增强。在电池循环过程中，NaS/NaS浓度的增加会诱导三维NaS沉积的形成，并减少电极有效电活性区域的覆盖范围，从而降低电池极化，尤其是在高倍率下。此外，较高的NaS/NaS溶解度可以促进“死NaS/NaS”的重复利用，大大提高活性材料的利用率。 2C倍率下，800次循环后仍能保持351mAh g，每循环容量衰减为0.046%。电池的倍率和循环性能大大提高。此外，还提出了一种通过过电势和扩散理论来增强电池性能的机制。