Li Miaoran, Peng Huiyuan, Pei Yang, Wang Fang, Zhu Ying, Shi Ruyue, He Xuexia, Lei Zhibin, Liu Zonghuai, Sun Jie
Key Laboratory of Applied Surface and Colloid Chemistry (MOE), Shaanxi Key Laboratory for Advanced Energy Devices, Shaanxi Engineering Laboratory for Advanced Energy Technology, School of Materials Science and Engineering, Shaanxi Normal University, 620 West Chang'an Street, Xi'an, Shaanxi 710119, China.
Nanoscale. 2020 Dec 8;12(46):23636-23644. doi: 10.1039/d0nr05727d.
Lithium sulfur batteries are expected to be one of the most promising energy storage systems due to their high energy density, low cost and environmental friendliness. However, the shuttle effect of lithium polysulfides severely hampers their practical application. The design of the sulfur cathode is one of the most important approaches to overcome the problem. In this work, MoS2 nanosheets have been successfully grown on the surface of hollow carbon spheres (HCS) to obtain MoS2@HCS nanocomposites with uniform morphology. The growth behavior of MoS2 nanosheets was also proved by adjusting the pore structure of HCS. With a sulfur loading of 74%, the MoS2@HCS/S cathode exhibits a high initial reversible capacity of 1419 mA h g-1 at a current density of 0.1 C and remains at 1010 mA h g-1 after 100 cycles. Even at 0.5 C, a capacity of 795 mA h g-1 can be retained after 600 cycles, corresponding to a capacity retention rate of 63.1%. By adjusting the concentration of the sulfur source, the relationship between different growth quantities of MoS2 and the cycling performance of the battery was also investigated. The excellent electrochemical performance of the MoS2@HCS/S cathode can be fully attributed to its physical and chemical double adsorption effect on lithium polysulfides, which has been confirmed through the visible adsorption and X-ray Photoelectron Spectroscopy (XPS) experiments. This work provides a simple design concept and method to synthesize a nanocomposite-based sulfur host for high performance lithium sulfur batteries.
锂硫电池因其高能量密度、低成本和环境友好性，有望成为最具前景的储能系统之一。然而，多硫化锂的穿梭效应严重阻碍了它们的实际应用。硫正极的设计是克服该问题的最重要方法之一。在这项工作中，二硫化钼纳米片已成功生长在空心碳球（HCS）表面，以获得具有均匀形态的二硫化钼@空心碳球纳米复合材料。通过调节空心碳球的孔结构，也证实了二硫化钼纳米片的生长行为。在硫负载量为74%时，二硫化钼@空心碳球/硫正极在0.1 C的电流密度下表现出1419 mA h g-1的高初始可逆容量，100次循环后仍保持在1010 mA h g-1。即使在0.5 C下，600次循环后仍可保持795 mA h g-1的容量，对应容量保持率为63.1%。通过调节硫源浓度，还研究了不同生长量的二硫化钼与电池循环性能之间的关系。二硫化钼@空心碳球/硫正极优异的电化学性能可完全归因于其对多硫化锂的物理和化学双重吸附作用，这已通过可见光吸附和X射线光电子能谱（XPS）实验得到证实。这项工作提供了一种简单的设计概念和方法，用于合成基于纳米复合材料的高性能锂硫电池硫主体。
