Supporting Information
A Novel Graphene-Polysulfide Anode Material for
High-Performance Lithium-Ion Batteries
Wei Ai1,2, Linghai Xie2, Zhuzhu Du2, Zhiyuan Zeng3, Juqing Liu3,4, Hua Zhang3, Yunhui Huang5, Wei
Huang*2, 4 and Ting Yu*1, 6
1
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang
Technological University, 637371, Singapore
2 Key
Laboratory for Organic Electronics & Information Displays (KLOEID) and Institute of Advanced
Materials (IAM), Nanjing University of Posts and Telecommunications, 9 Wenyuan Road, Nanjing
210046, P. R. China
3 School
4
of Materials Science and Engineering, Nanyang Technological University, 639798, Singapore
Jiangsu-Singapore Joint Research Center for Organic/Bio-Electronics & Information Displays and
Institute of Advanced Materials, Nanjing University of Technology, Nanjing 211816, P. R. China
5
State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials
Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P.
R. China
6 Department
of Physics, Faculty of Science, National University of Singapore, 117542, Singapore
Corresponding author: yuting@ntu.edu.sg; wei-huang@njupt.edu.cn
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Figure S1 | C 1s XPS spectra of GO and GPS materials: a, GO, b, G2S, c, G3S, d, G4S and e, G5S.
The C 1s XPS spectra of original GO (Fig. S1a) consists of four peaks arising from C-C (284.5 eV), CO (286.7 eV), C=O (288.0 eV) and O-C=O (288.9 eV). While the peak intensity for oxygen-containing
groups have been dramatically decreased in GPS materials (Fig. S1b-e), indicating the successful
reduction by hydrazine. Moreover, the additional C-N (285.4 eV) is also observed in G2S, G3S, G4S
and G5S, which is attributed to the aromatic nitrogen doping during the reduction with hydrazine1.
2
Figure S2 | XPS survey spectra of GO, G2S, G3S, G4S and G5S. Compared with GO, the decreased
intensity of the O 1s peaks and increased intensity of the C 1s indicates the reduction of GPS materials.
Notably, S 2p peak at 162.1 eV is clearly seen in the spectra of the GPS materials, demonstrating the
sulfur has been effectively introduced to graphene sheets.
3
Figure S3 | High-resolution S 2P XPS spectra of GPS materials: a, G2S, b, G3S and c, G4S, the
peaks at about 163.4 and 164.7 eV corresponds to the C-S bonds and S-S bonds, respectively, indicating
the polysulfide bonds have been successfully introduced to the graphene sheets. d, S content data and
C/O ratio in GO, G2S, G3S, G4S and G5S, determined from the obtained XPS spectra.
4
Figure S4 | Raman spectra of GO, G2S, G3S, G4S and G5S.
Figure S5 | XRD patterns of GO, Graphite, G2S, G3S, G4S and G5S.
5
Figure S6 | a, Photograph of a GO dispersion in water. b, Tapping-mode Atomic force microscopy
(AFM) image of GO on Si/SiO2 substrate. The exfoliated GO is found to be hundreds nanometers to
several micrometers in lateral dimensions and the thickness of a single-layer GO is about 1.1 nm.
Figure S7 | FESEM images of GO and GPS materials: a, GO, b, G2S, c G3S and d, G4S. Inset: EDS
spectra of GPS showing the presence of sulfur, the content of sulfur increases with increasing the length
of polysulfide chain.
6
Figure S8 | The total atomic ratios in the GPS samples, calculated by EDS analysis.
Figure S9 | TGA curves of GO and GPS materials at heating rate 5 oC min-1 under nitrogen
atmosphere.
7
Figure S10 | TEM images and elemental mapping images of GO: TEM image of a, GO and the
corresponding elemental mapping images of b, carbon and c, oxygen in the selected area, indicating the
homogeneous distribution of oxygen in GO.
Figure S11 | TEM images and elemental mapping images of G4S materials: TEM images of a, G4S,
with corresponding elemental mapping images of b, carbon and c, sulfur in the selected area, indicating
the homogeneous distribution of sulfur in G4S.
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Figure S12 | Schematic diagram of GPS as active material in rechargeable lithium batteries. The
redox reaction on GPS electrodes processed in two steps as shown in Fig. S112.
Figure S13 | Electrochemical lithium storage performance of G2S, G3S and G4S electrode: CV
curves of the a, G2S, d, G3S and g, G4S electrode at a scan rate of 0.5 mV s-1 over a voltage range of
0.005 to 3.0 V (vs. Li/Li+). The discharge-charge curves of b, G2S, e, G3S, h, G4S electrode at a current
of 250 mA g-1. Cycling performance of the c, G2S, f, G3S and i, G4S electrode tested at a current
density of 250 mA g-1.
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Figure S14 | High-resolution S 2P XPS spectra of G5S after 400 cycles at a current of 250 mA/g.
The C-S bonds (163.43 eV) and S-S bonds (164.67 eV) can also be observed after 400 cycles, indicating
the dissolution of polysulfides can be effectively prevented due to the covalent bond between the
polysulfides and graphene. The peak at 169.45 eV could be attributed to the unwashed sulfate ion in
GPS materials3.
Figure S15 | Morphological analysis of G5S electrodes before and after charge/discharge cycling
tests: FESEM images of G5S electrodes a, at first cycle, b, after 50th cycle, c, after 150th cycle.
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Figure S16 | Electrochemical impedance spectra of the GPS materials. EIS plots of GPS electrodes
obtained by applying amplitude of 5.0 mV over the frequency range from 100 kHz to 0.01 Hz.
References
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nitrogen doping. Nat Commun 3, 638 (2012).
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Electrochemistry of Sulfur-Poly(acrylonitrile) Composite Cathode Materials for Rechargeable
Lithium Batteries. Chem. Mater. 23, 5024-5028 (2011).
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apatite formation in a simulated body fluid. J. Mater. Chem. 17, 4057-4063 (2007).
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