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In Situ Formed Protective Barrier Enabled by Sulfur@Titanium Carbide (MXene) Ink for Achieving High‐Capacity, Long Lifetime Li‐S Batteries
Advanced Science ( IF 14.3 ) Pub Date : 2018-07-04 , DOI: 10.1002/advs.201800502
Huan Tang 1 , Wenlong Li 1 , Limei Pan 1 , Conor P Cullen 2 , Yu Liu 3 , Amir Pakdel 2 , Donghui Long 3 , Jian Yang 1 , Niall McEvoy 2 , Georg S Duesberg 2, 4 , Valeria Nicolosi 2 , Chuanfang John Zhang 2
Affiliation  

Sulfur (S) is an attractive cathode material with advantages including high theoretical capacity and low cost. However, issues such as the lithium polysulfide shuttle effect and its insulating properties greatly limit the future applications of lithium‐sulfur (Li‐S) batteries. Here, a viscous aqueous ink with nanoscale S uniformly decorated on the polar, metallically conductive titanium carbide MXene nanosheets (S@Ti3C2Tx) is reported to address these issues. Importantly, it is observed that the conductive Ti3C2Tx mediator efficiently chemisorbs the soluble polysulfides and converts them into thiosulfate/sulfate. The in situ formed sulfate complex layer acts as a thick protective barrier, which significantly retards the shuttling of polysulfides upon cycling and improves the sulfur utilization. Consequently, the binder‐free, robust, highly electrically conductive composite film exhibits outstanding electrochemical performance, including high capacities (1244–1350 mAh g‐1), excellent rate handling, and impressive cycling stability (0.035–0.048% capacity loss per cycle), surpassing the best MXene‐S batteries known. The fabrication of a pouch cell based on the freestanding S@Ti3C2Tx film is also reported. The prototype device showcases high capacities and excellent mechanical flexibility. Considering the broad family of MXenes and their unique roles in immobilizing the polysulfides, various S@MXene composites can be similarly fabricated with promising Li+ storage capability and long lifetime performance.

中文翻译:


通过硫@碳化钛 (MXene) 墨水原位形成保护屏障,实现高容量、长寿命的锂硫电池



硫(S)是一种颇具吸引力的正极材料,具有理论容量高、成本低等优点。然而,多硫化锂穿梭效应及其绝缘性能等问题极大地限制了锂硫(Li-S)电池的未来应用。在此,报道了一种在极性金属导电碳化钛 MXene 纳米片 (S@Ti 3 C 2 T x ) 上均匀装饰纳米级 S 的粘性水性墨水,以解决这些问题。重要的是,观察到导电Ti 3 C 2 T x介体有效地化学吸附可溶性多硫化物并将其转化为硫代硫酸盐/硫酸盐。原位形成的硫酸盐络合物层充当了厚厚的保护屏障,显着阻碍了循环时多硫化物的穿梭并提高了硫的利用率。因此,无粘合剂、坚固、高导电性的复合薄膜表现出出色的电化学性能,包括高容量(1244-1350 mAh g -1 )、出色的倍率处理和令人印象深刻的循环稳定性(每次循环容量损失0.035-0.048%) ,超越了已知最好的 MXene-S 电池。还报道了基于独立式 S@Ti 3 C 2 T x薄膜的软包电池的制造。该原型设备展示了高容量和出色的机械灵活性。考虑到 MXene 的广泛家族及其在固定多硫化物方面的独特作用,可以类似地制造各种 S@MXene 复合材料,并具有良好的 Li +存储能力和长寿命性能。
更新日期:2018-07-04
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