PEO-Linked MoS2-Graphene Nanocomposites with 2D Polar-Nonpolar Amphoteric Surfaces as Sulfur Hosts for High-Performance Li-S Batteries
PEO-Linked MoS2-Graphene Nanocomposites with 2D Polar-Nonpolar Amphoteric Surfaces as Sulfur Hosts for High-Performance Li-S Batteries
复制标题
具有二维极性-非极性两性表面的 PEO 连接的 MoS2-石墨烯纳米复合材料作为高性能锂硫电池的硫主体
DOI：
10.1021/acssuschemeng.7b03306
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发表时间：
2018-01-01
影响因子：
8.4
通讯作者：
Shi, Jianlin
中科院分区：
文献类型：
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作者：
Sun, Fugen;Tang, Hao;Shi, Jianlin
通过极性MoS 2层与聚环氧乙烷交联的非极性石墨烯的组装，成功制备了具有二维极性非极性两性表面的层状MoS 2石墨烯纳米复合材料，用于锂硫电池的限硫。受益于石墨烯的高导电性和极性MoS 2与多硫化物之间的强化学键合，MoS 2石墨烯复合材料不仅确保了与绝缘硫的不受阻碍的导电，而且还有效地将多硫化物捕获在其中。非原位研究进一步揭示了MoS 2石墨烯复合材料通过将固体Li 2S产物优先沉积到极性MoS 2层上来实现空间调节的Li 2S沉积，使得大量的快速电子传输路径暴露在石墨烯上用于进一步的硫还原。因此，所获得的MoS 2硫石墨烯纳米复合材料呈现出优异的倍率性能和循环稳定性，具有在0.2C下100次循环后895 mA h g（-1）和在1C下200次循环后524 mA h g（-1）的高可逆容量。这些令人鼓舞的结果表明，通过合理整合二维极性和非极性两性表面的层状结构的硫阴极材料将是一个有前途的策略，以提高先进的锂S电池的电化学性能。
Layered MoS2 graphene nanocomposites with 2D polar nonpolar amphoteric surfaces, which were used to confine sulfur for Li S batteries, have been successfully fabricated through the assembly of polar MoS2 layers and nonopolar graphene with poly(ethylene oxide) cross-linking. Benefiting from the high conductivity of graphene and the strong chemical bonding between polar MoS2 and polysulfides, the MoS2 graphene composites not only ensure unimpeded electrical conducting to the insulating sulfur but also effectively entrap polysulfides therein. The ex situ study further reveals that the MoS2 graphene composites enable spatially regulated Li2S deposition by the preferential deposition of solid Li2S product onto the polar MoS2 layers, making a large amount of fast electron transport paths exposed on graphene for further sulfur reduction. Therefore, the obtained MoS2 sulfur graphene nanocomposites present excellent rate performance and cycling stability with high reversible capacities of 895 mA h g(-1) at 0.2 C after 100 cycles and 524 mA h g(-1) at 1 C after 200 cycles. These encouraging results suggest that the layer-structured sulfur cathode materials through the rational integration of 2D polar and nonpolar amphoteric surfaces would be a promising strategy for enhancing the electrochemical performances of advanced Li S batteries.