Functional binders constitute a strategy to overcome several challenges that lithium-sulfur (Li-S) batteries are facing due to soluble reaction intermediates in the positive electrode. Poly (ethylene oxide) (PEO) and poly (vinylpyrrolidone) (PVP) are in this context a previously well-explored binder mixture. Their ether and amide groups possess affinity to the dissolved sulfur species, which enhances the sulfur utilization and mitigates the parasitic redox shuttle. However, the immiscibility of PEO and PVP is a concern for electrode stability. Copolymers comprising ether and amide groups are thus promising candidates to improve the stability the system. Here, a series of poly (ethylene glycol-block-2-ethyl-2-oxazoline) with various block lengths is synthesized and explored as binders in S/C composite electrodes in Li-S cells. While the electrochemical analyses show that although the sulfur utilization and capacity retention of the tested electrodes are similar, the integrity of the as-cast electrodes can play a key role for power capability.

中文翻译：

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聚（乙二醇-嵌段-2-乙基-2-恶唑啉）作为锂硫电池的阴极粘合剂

功能性粘合剂构成了克服锂硫 (Li-S) 电池由于正极中的可溶性反应中间体而面临的若干挑战的策略。在这种情况下，聚（环氧乙烷）（PEO）和聚（乙烯基吡咯烷酮）（PVP）是一种先前已充分探索的粘合剂混合物。它们的醚和酰胺基团对溶解的硫物质具有亲和力，从而提高了硫的利用率并减轻了寄生的氧化还原穿梭。然而，PEO 和 PVP 的不混溶性是电极稳定性的一个问题。因此，包含醚和酰胺基团的共聚物有望成为提高体系稳定性的候选者。这里，一系列聚（乙二醇-嵌段-2-乙基-2-恶唑啉）具有不同的嵌段长度，被合成并探索作为锂硫电池中 S/C 复合电极的粘合剂。虽然电化学分析表明，虽然测试电极的硫利用率和容量保持率相似，但铸态电极的完整性对功率容量起着关键作用。