Lithium-sulfur (Li-S) battery is a promising energy storage technology to replace lithium ion batteries for higher energy density and lower cost. Dissolution of lithium polysulfide intermediates in conventional Li-S electrolytes is known as one of the key technical barriers to the development of Li-S, because it promotes redistribution and irreversible deposition of Li₂S, and also forces large amounts of electrolyte to be used, shortening cycling life and driving down cell energy density. Recently, dimethyl disulfide as a functional co-solvent has been demonstrated to show an alternate electrochemical reaction pathway for sulfur cathodes by the formation of dimethyl polysulfides and lithium organosulfides as intermediates and reduction products. In this work, comprehensive studies show that this new pathway not only provides high capacity but also enables excellent capacity retention through a built-in automatic discharge shutoff mechanism by tuning carbon/sulfur ratio in sulfur cathodes to reduce unfavorable Li₂S formation. Furthermore, this new electrolyte system is also found to enable high capacity of high-sulfur-loading cathodes with low electrolyte/sulfur (E/S) ratios, such as a stable specific capacity of around 1000mAhg⁻¹ using a low electrolyte amount (i.e, E/S ratio of 5mLg⁻¹) and high-sulfur-loading (4mgcm⁻²) cathodes. This electrolyte system almost doubles the capacity obtained with conventional electrolytes under the same harsh conditions. These results highlight the practical potential of this electrolyte system to enable high-energy-density Li-S batteries.

中文翻译：

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含有机硫化物的电解质使低硫/硫比的锂硫电池具有高容量

锂硫（Li-S）电池是一种有前途的储能技术，可代替锂离子电池以实现更高的能量密度和更低的成本。已知多硫化锂中间体在常规Li-S电解质中的溶解是发展Li-S的关键技术障碍之一，因为它会促进Li _2的重新分布和不可逆沉积。S，并且还迫使使用大量电解质，从而缩短循环寿命并降低电池能量密度。最近，通过形成二甲基多硫化物和有机硫化锂为中间体和还原产物，已证明二甲基二硫化物作为功能性助溶剂显示出用于硫阴极的另一种电化学反应途径。在这项工作中，综合研究表明，这种新途径不仅可以提供高容量，而且还可以通过调节硫阴极中的碳/硫比以减少不利的Li ₂的内置自动放电关闭机制，实现出色的容量保持率。S阵型。此外，还发现这种新的电解质系统可实现高容量的低硫/硫（E / S）比的高硫负载阴极，例如使用低电解质量（例如，约1000mAhg ^-1的稳定比容量），E / S比为5mLg ^-1）和高硫负载（4mgcm ^-2）阴极。在相同的苛刻条件下，该电解质系统的容量几乎是传统电解质的两倍。这些结果突出了该电解质系统在实现高能量密度Li-S电池方面的实际潜力。