A sulfur-enriched solid electrolyte interface (SEI) is known to enhance the cycling stability of a Li metal electrode, however, using the conventional additive approach, the positive effect is hard to maintain during prolonged cycling. Here, we present a method of forming a sulfur-enriched SEI in sustainable manner during battery cycling. A polymer electrolyte layer containing a sulfur chain is inserted between the lithium metal electrode and liquid electrolyte phase. The interfacial layers of the poly(α-lipoic acid-co-sulfur) readily form Li₂S and Li₂S₂ at the Li metal surface, inducing dendrite-free, planar Li deposition beneath the layer. As a result of the regeneration of the sulfur-enriched SEI during repeated cycling, a Li metal electrode with the interfacial layer in a Li symmetric cell operated for more than 400 cycles at a high current density of 3 mA cm^–2 and a high areal capacity of 3 mAh cm^–2. The SEI-forming interfacial layer approach provides sustainable protection of the Li metal electrode during prolonged cycling in Li metal batteries.

中文翻译：

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含硫链的聚合物电解质界面层在锂金属电极上可持续形成富硫固体电解质界面

众所周知，富硫固体电解质界面（SEI）可以增强锂金属电极的循环稳定性，但是，使用常规的添加剂方法，很难在长时间循环中保持积极的作用。在这里，我们提出一种在电池循环过程中以可持续的方式形成富硫SEI的方法。在锂金属电极与液体电解质相之间插入含有硫链的聚合物电解质层。聚（α-硫辛酸-共硫）的界面层容易形成Li ₂ S和Li ₂ S ₂在锂金属表面上，导致在层下方无枝晶状的平面锂沉积。由于重复循环过程中富硫SEI的再生，在Li对称电池中具有界面层的Li金属电极在3 mA cm ^–2的高电流密度和高面积下工作了400多个循环容量为3 mAh cm ^–2。形成SEI的界面层方法可在锂金属电池的长时间循环中为锂金属电极提供可持续的保护。