title: Graphene-based three-dimensional hierarchical sandwich-type architecture for high-performance Li/S batteries.
abstract: A multiwalled carbon nanotube/sulfur (MWCNT@S) composite with core-shell structure was successfully embedded into the interlay galleries of graphene sheets (GS) through a facile two-step assembly process. Scanning and transmission electron microscopy images reveal a 3D hierarchical sandwich-type architecture of the composite GS-MWCNT@S. The thickness of the S layer on the MWCNTs is ~20 nm. Raman spectroscopy, X-ray diffraction, thermogravimetric analysis, and energy-dispersive X-ray analysis confirm that the sulfur in the composite is highly crystalline with a mass loading up to 70% of the composite. This composite is evaluated as a cathode material for Li/S batteries. The GS-MWCNT@S composite exhibits a high initial capacity of 1396 mAh/g at a current density of 0.2C (1C = 1672 mA/g), corresponding to 83% usage of the sulfur active material. Much improved cycling stability and rate capability are achieved for the GS-MWCNT@S composite cathode compared with the composite lacking GS or MWCNT. The superior electrochemical performance of the GS-MWCNT@S composite is mainly attributed to the synergistic effects of GS and MWCNTs, which provide a 3D conductive network for electron transfer, open channels for ion diffusion, strong confinement of soluble polysulfides, and effective buffer for volume expansion of the S cathode during discharge.
authors.affiliation: Beijing Key Laboratory of Environmental Science and Engineering, School of Chemical Engineering and Environment, Beijing Institute of Technology , Beijing, 100081, China.
authors.forename: Renjie
authors.initials: R
authors.lastname: Chen
authors.forename: Teng
authors.initials: T
authors.lastname: Zhao
authors.forename: Jun
authors.initials: J
authors.lastname: Lu
authors.forename: Feng
authors.initials: F
authors.lastname: Wu
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Junzheng
authors.initials: J
authors.lastname: Chen
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Tan
authors.forename: Yusheng
authors.initials: Y
authors.lastname: Ye
authors.forename: Khalil
authors.initials: K
authors.lastname: Amine
mesh_terms: D011211:Electric Power Supplies; D006108:Graphite / Q000737:chemistry*; D007477:Ions; D008094:Lithium / Q000737:chemistry*; D037742:Nanotubes, Carbon / Q000737:chemistry; D013455:Sulfur / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D007477:Ions; D037742:Nanotubes, Carbon; D013455:Sulfur; D006108:Graphite; D008094:Lithium