Wang Dan-Yang, Guo Wei, Fu Yongzhu
College of Chemistry , Zhengzhou University , Zhengzhou 450001 , P. R. China.
Acc Chem Res. 2019 Aug 20;52(8):2290-2300. doi: 10.1021/acs.accounts.9b00231. Epub 2019 Aug 6.
Lithium-ion batteries have received significant attention over the last decades due to the wide application of portable electronics and increasing deployment of electric vehicles. In order to further increase the energy density of batteries and overcome the capacity limitations (<250 mAh g) of inorganic cathode materials, it is imperative to explore new cathode materials for rechargeable lithium batteries. Organic compounds including organic carbonyl, radicals, and organosulfides are promising as they have advantages of high capacities, abundant resources, and tunable structures. In the 1980s, a few organosulfides, in particular organodisulfides, as cathode materials were studied to a certain extent in rechargeable lithium batteries. However, they showed low capacities and poor cycling performance, which made them unappealing then in comparison to transition metal oxide cathode materials. As a result, organosulfides have not been extensively studied like other cathode materials including organic carbonyls and radicals. In recent years, organosulfides with long sulfur chains (e.g., trisulfide, tetrasulfide, pentasulfide, etc.) in the structures have been receiving more attention in conjunction with the development of lithium-sulfur batteries. As a major class of sulfur derivatives, they have versatile structures and unique properties in comparison with elemental sulfur. In this Account, we first generalize the working principles of organosulfides in lithium batteries. We then discuss organosulfide molecules, which have precise lithiation sites and tunable capacities. The organic functional groups can provide additional benefits, such as discharge voltage and energy efficiency enhancement by phenyl groups and cycling stability improvement by N-heterocycles. Furthermore, replacing sulfur by selenium in these compounds can improve their electrochemical properties due to the high electronic conductivity and low bond energy associated with selenium. We list organosulfide polymers consisting of phenyl rings, N-heterocycles, or aliphatic segments. Organosulfides as electrolyte additives or components for forming a solid-electrolyte interphase layer on lithium metal anode are also presented. Carbon materials such as carbon nanotubes and reduced graphene oxide can enhance the battery performance of organosulfide cathodes. We discuss the synthesis methods for polysulfide molecules and polymers. Finally, we show the advantages of organosulfides over sulfur as cathode materials in lithium batteries. This Account provides a summary of recent development, in-depth analysis of structure-performance relationship, and guidance for future development of organosulfides as promising cathode materials for next generation rechargeable lithium batteries.
在过去几十年里，锂离子电池因其在便携式电子设备中的广泛应用以及电动汽车的日益普及而备受关注。为了进一步提高电池的能量密度并克服无机正极材料的容量限制（<250 mAh g），探索用于可充电锂电池的新型正极材料势在必行。包括有机羰基、自由基和有机硫化物在内的有机化合物具有潜力，因为它们具有高容量、资源丰富和结构可调控的优点。在20世纪80年代，一些有机硫化物，特别是有机二硫化物，作为正极材料在可充电锂电池中得到了一定程度的研究。然而，它们表现出低容量和较差的循环性能，这使得它们与过渡金属氧化物正极材料相比缺乏吸引力。因此，与包括有机羰基和自由基在内的其他正极材料相比，有机硫化物尚未得到广泛研究。近年来，随着锂硫电池的发展，结构中含有长硫链（如三硫化物、四硫化物、五硫化物等）的有机硫化物受到了更多关注。作为一类主要的硫衍生物，与元素硫相比，它们具有多样的结构和独特的性质。在本综述中，我们首先概括了有机硫化物在锂电池中的工作原理。然后讨论了具有精确锂化位点和可调控容量的有机硫化物分子。有机官能团可以提供额外的益处，例如苯基可提高放电电压和能量效率，氮杂环可改善循环稳定性。此外，在这些化合物中用硒取代硫可以改善其电化学性能，因为硒具有高电子导电性和低键能。我们列出了由苯环、氮杂环或脂肪族链段组成的有机硫化物聚合物。还介绍了有机硫化物作为电解质添加剂或用于在锂金属阳极上形成固体电解质界面层的成分。碳纳米管和还原氧化石墨烯等碳材料可以提高有机硫化物正极的电池性能。我们讨论了多硫化物分子和聚合物的合成方法。最后，我们展示了有机硫化物作为锂电池正极材料相对于硫的优势。本综述总结了近期的发展情况，深入分析了结构 - 性能关系，并为有机硫化物作为下一代可充电锂电池有前景的正极材料的未来发展提供了指导。
