A long-life lithium–sulfur battery requires insulation of the dissolved polysulfide intermediates from the reactive anode. However, there exists a trade-off between preventing polysulfide dissolution and facilitating the sulfur redox reactions. Here, an in situ encapsulation strategy for sulfur/carbon (S/C) composite cathode is developed. We employ antimony trifluoride as a bi-functional pre-coating layer on the S/C composite surface. During the in situ encapsulation process, the liquid electrolyte can wet the S/C composite; while being catalyzed by antimony trifluoride, the liquid electrolyte can polymerize to form a dense lithium-ion-conducting solid polymer electrolyte (SPE) layer on the S/C composite surface. Additionally, antimony trifluoride proves to have strong anchoring effects on polysulfides, which works together with the SPE layer to suppress polysulfide dissolution. The in situ encapsulated cathode enhances the cyclability with a minor sacrifice in the rate capability. It is further demonstrated that the cathode can be directly paired with a non-protected lithiated silicon anode to achieve a practical capacity retention rate of 87% for 200 cycles.

中文翻译：

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锂硫电池中多硫化物保留的原位封装方法

长寿命的锂硫电池需要将溶解的多硫化物中间体与反应性阳极绝缘。然而，在防止多硫化物溶解和促进硫氧化还原反应之间存在折衷。在这里，开发了硫/碳（S / C）复合阴极的原位封装策略。我们将三氟化锑用作S / C复合材料表面上的双功能预涂层。在原地封装过程中，液体电解质可以润湿S / C复合材料；在被三氟化锑催化的同时，液体电解质可以聚合以在S / C复合材料表面上形成致密的传导锂离子的固体聚合物电解质（SPE）层。另外，三氟化锑被证明对多硫化物具有很强的锚固作用，它与SPE层一起可抑制多硫化物的溶解。在原地封装阴极增强了在速度能力的未成年人的牺牲可循环性。进一步证明，阴极可以与未保护的锂化硅阳极直接配对，以在200个循环中实现87％的实际容量保持率。