Department of Chemical and Biomolecular Engineering, National University of Singapore, 10 Kent Ridge Crescent, Singapore 119260.
Nanoscale. 2013 Sep 7;5(17):7890-6. doi: 10.1039/c3nr02920d.
Two-dimensional nanosheets can leverage on their open architecture to support facile insertion and removal of Li(+) as lithium-ion battery electrode materials. In this study, two two-dimensional nanosheets with complementary functions, namely nitrogen-doped graphene and few-layer WS2, were integrated via a facile surfactant-assisted synthesis under hydrothermal conditions. The layer structure and morphology of the composites were confirmed by X-ray diffraction, scanning electron microscopy and high-resolution transmission microscopy. The effects of surfactant amount on the WS2 layer number were investigated and the performance of the layered composites as high energy density lithium-ion battery anodes was evaluated. The composite formed with a surfactant : tungsten precursor ratio of 1 : 1 delivered the best cyclability (average of only 0.08% capacity fade per cycle for 100 cycles) and good rate performance (80% capacity retention with a 50-fold increase in current density from 100 mA g(-1) to 5000 mA g(-1)), and may find uses in power-oriented applications.
二维纳米片可以利用其开放架构来支持锂离子电池电极材料中 Li(+)的方便插入和去除。在这项研究中，通过在水热条件下通过简便的表面活性剂辅助合成，将两种具有互补功能的二维纳米片，即氮掺杂石墨烯和少层 WS2，进行了集成。通过 X 射线衍射、扫描电子显微镜和高分辨率透射显微镜确认了复合材料的层结构和形貌。研究了表面活性剂用量对 WS2 层数的影响，并评估了层状复合材料作为高能量密度锂离子电池负极的性能。在表面活性剂与钨前体的比例为 1:1 时形成的复合材料具有最佳的循环稳定性（100 次循环中平均每个循环的容量衰减仅为 0.08%）和良好的倍率性能（电流密度从 100 mA g(-1)增加到 5000 mA g(-1)时，容量保持率为 80%），可能适用于面向功率的应用。
