Bai Zhongchao, Zhang Yaohui, Zhang Yuwen, Guo Chunli, Tang Bin
Research Institute of Surface Engineering, Taiyuan University of Technology, Taiyuan, 030024 (P. R. China).
Chemistry. 2015 Dec 7;21(50):18187-91. doi: 10.1002/chem.201503587. Epub 2015 Nov 6.
Hierarchical hybridized nanocomposites with rationally constructed compositions and structures have been considered key for achieving superior Li-ion battery performance owing to their enhanced properties, such as fast lithium ion diffusion, good collection and transport of electrons, and a buffer zone for relieving the large volume variations during cycling processes. Hierarchical MoS2 @carbon microspheres (HMCM) have been synthesized in a facile hydrothermal treatment. The structure analyses reveal that ultrathin MoS2 nanoflakes (ca. 2-5 nm) are vertically supported on the surface of carbon nanospheres. The reversible capacity of the HMCM nanocomposite is maintained at 650 mA h g(-1) after 300 cycles at 1 A g(-1) . Furthermore, the capacity can reach 477 mA h g(-1) even at a high current density of 4 A g(-1) . The outstanding electrochemical performance of HMCM is attributed to the synergetic effect between the carbon spheres and the ultrathin MoS2 nanoflakes. Additionally, the carbon matrix can supply conductive networks and prevent the aggregation of layered MoS2 during the charge/discharge process; and ultrathin MoS2 nanoflakes with enlarged surface areas, which can guarantee the flow of the electrolyte, provide more active sites and reduce the diffusion energy barrier of Li(+) ions.
具有合理构建的组成和结构的分级杂化纳米复合材料,因其具有诸如快速锂离子扩散、良好的电子收集和传输以及用于缓解循环过程中大量体积变化的缓冲区域等增强性能,而被认为是实现卓越锂离子电池性能的关键。通过简便的水热法合成了分级MoS₂@碳微球(HMCM)。结构分析表明,超薄MoS₂纳米片(约2 - 5nm)垂直支撑在碳纳米球表面。HMCM纳米复合材料在1 A g⁻¹下循环300次后,可逆容量保持在650 mA h g⁻¹。此外,即使在4 A g⁻¹的高电流密度下,容量也能达到477 mA h g⁻¹。HMCM出色的电化学性能归因于碳球与超薄MoS₂纳米片之间的协同效应。此外,碳基体可以提供导电网络,并在充放电过程中防止层状MoS₂的聚集;而具有更大表面积的超薄MoS₂纳米片,可以保证电解质的流动,提供更多活性位点并降低Li⁺离子的扩散能垒。