CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China.
Nanotechnology. 2017 Dec 8;28(49):495701. doi: 10.1088/1361-6528/aa91f1.
Lithium-sulfur batteries have attracted great concern because of the high theoretical capacity of sulfur (1675 mA h g). However, the poor electrical conductivity and volumetric expansion of sulfur along with the dissolution of lithium polysulfides largely limit their practical application. In this study, nitrogen-doped graphene aerogel (NGA) with high nitrogen content and porosity is used as a host for the impregnation of sulfur. The effects of sulfur impregnation on the specific surface area, pore volume, and microstructure of NGA supported sulfur composite (S@NGA) are well investigated. Furthermore, NGA is also processed into a NGA film, which is sandwiched between a separator and S@NGA cathode. The lithium-sulfur battery with such a configuration delivers a high reversible capacity of 1514 mA h g at 0.1 C, excellent rate performance (822 mA h g at 2.0 C), and good cycling stability (946 mA h g at 0.5 C even after 100 cycles). The enhanced electrochemical performance can be ascribed to the introduction of the NGA interlayer, the unique interconnected porous structure, and strong interaction between the three-dimensional nitrogen-doped graphene network and the homogeneously dispersed sulfur and/or lithium polysulfides.
锂硫电池因其硫的理论容量高（1675 mA h g）而受到广泛关注。然而，硫的电导率差和体积膨胀以及多硫化锂的溶解在很大程度上限制了它们的实际应用。在本研究中，高氮含量和多孔性的氮掺杂石墨烯气凝胶（NGA）被用作浸渍硫的载体。研究了硫浸渍对 NGA 负载硫复合材料（S@NGA）的比表面积、孔体积和微观结构的影响。此外，NGA 还被加工成 NGA 薄膜，夹在分离器和 S@NGA 阴极之间。具有这种结构的锂硫电池在 0.1 C 时具有 1514 mA h g 的高可逆容量、优异的倍率性能（2.0 C 时为 822 mA h g）和良好的循环稳定性（即使在 100 次循环后，在 0.5 C 时仍为 946 mA h g）。电化学性能的提高可归因于 NGA 中间层的引入、独特的互连多孔结构以及三维氮掺杂石墨烯网络与均匀分散的硫和/或多硫化锂之间的强相互作用。
