Copyright WILEY‐VCH Verlag GmbH & Co. KGaA, 69469 Weinheim, Germany, 2015. Supporting Information for Adv. Funct. Mater., DOI: 10.1002/adfm.201503010 Transition-Metal-Free Magnesium-Based Batteries Activated
by Anionic Insertion into Fluorinated Graphene Nanosheets
Junjie Xie, Chilin Li,* Zhonghui Cui, and Xiangxin Guo
Copyright WILEY-VCH Verlag GmbH & Co. KGaA, 69469 Weinheim, Germany, 2013.
Supporting Information
Transition Metal Free Magnesium-Based Batteries Activated by Anionic
Insertion into Fluorinated Graphene Nanosheets
Junjie Xie, Chilin Li*, Zhonghui Cui, and Xiangxin Guo
[*] Dr. Junjie Xie, Prof. Chilin Li, Dr. Zhonghui Cui, Prof. Xiangxin Guo
State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai
Institute of Ceramics, Chinese Academy of Sciences, 1295 Ding Xi Road, Shanghai 200050,
China
E-mail: [email protected]
Table S1. Atomic content of elemental C, O and F in FGS and RGO samples from XPS
estimation. The relative atomic content of C to F (RC/F) for FGS is estimated to be 9.72, and
the relative contents of C to O (RC/O) for RGO (8.13) and FGS (8.57) are almost same. It
means that fluorination does not cause a more in-depth deoxygenation and some oxygenated
functional groups of GO are difficult to be removed during relatively mild hydrothermal
reaction.
Head
RGO
FGS
C (%)
88.16
81.18
O(%)
10.84
9.47
F(%)
-
8.35
RC/O(%)
8.13
8.57
FC/F(%)
-
9.72
1
Figure S1. Raman spectra of FGS and RGO under the excitation of 532 nm. It shows that the
intensity ratio of D and G peaks (ID/IG) for FGS (1.06) is similar to that for RGO (1.07),
indicating that fluorination does not significantly influence the order degree of carbon.
Figure S2. Galvanostatic charge/discharge curves of Mg/RGS battery with a lower upper cutoff voltage of 2.5 V during the first six cycles at 10 mA/g. The discharge process is performed
first during the initial cycle. Note that the reversible capacity is as low as 40-50 mAh/g, which
is much lower than that with a higher cut-off voltage of 2.75 V.
2
Figure S3. Comparsion of XPS spectra of (a) Cl2p and (b) O1s between the samples after the
initial discharge and charge. Different from the case of first charge, we cannot observe
remarkable Cl2p signal as well as O1s signal belonging to ClO4-. It indicates a negligible
insertion of ClO4- during the initial discharge and that the Cl2p signal indeed stems from the
first charge rather than the Cl residual after the initial discharge.
Figure S4. XPS peak area ratio of F-C and F-Mg bonds from F1s signals of FGS electrodes at
different charge/discharge stages. The peak area ratio of Mg-F in the sum of Mg-F (686 eV)
and C-F (687.6 eV) increases significantly from 26.5% after 1st charge to 75.7% after 2nd
discharge. This ratio value decreases to 39.5% after 2nd charge.
3
Figure S5. Ex-situ C1s XPS spectra of pristine and cycled FGS electrodes after 1st charge, 2nd
discharge and 2nd charge. C1s spectra show the similar tendency of peak intensity evolution as
F1s.
Table S2. Atomic contents of all the elements in FGS frameworks at different cycling stages
by XPS analysis. The negligible S concentrations in all the samples indicate that DMSO is
dissociated from the Mg2+-based complex cations when bonding of these solvates with
surface function groups of FGS. The presence of Mg and Cl components in the cycled
samples are also confirmed by STEM mapping.
Head
C(%) O (%) F(%) Mg(%) Cl(%) S (%)
FGS-Pristine
78.22
13.1
8.68
-
-
-
FGS-charge-1st
67.64
18.81
6.4
2.28
3.67
1.19
FGS-discharge-1st 46.75
32.09
6.02
7.84
7.24
-
FGS-charge-2nd
24.09
7.47
0.52
0.34
-
66.89
4