A comparative study of activated carbon-based symmetric
supercapacitors in Li2SO4 and KOH aqueous electrolytes
Xianzhong Sun, Xiong Zhang, Haitao Zhang, Dacheng Zhang, Yanwei Ma*
Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190,
PR China
* Corresponding author. Tel: +86-10-82547129; Fax: +86-10-82547137
E-mail address:
[email protected]
Figure S1
55
50
45
Solubility (g)
40
35
30
25
20
15
Li2SO4
10
K2SO4
5
Na2SO4
0
0
20
40
60
80
100
Temperature ( degree )
Fig. S1
Solubility of Li2SO4, K2SO4, and Na2SO4 in water at temperatures of 080
°C.
(Solubility data from the websites: http://en.wikipedia.org/wiki/Solubility_table;
http://srdata.nist.gov/solubility/index.aspx)
Figure S2
(a)
50
4
10
10
Z'' (ohm)
40
30
20
10
0
0
10
20
30
40
50
60
Z' (ohm)
(b)
80
O
Phase ( )
60
40
4
10
20
10
0
0.01
0.1
1
10
100
1000
10000 100000
Frequency (Hz)
Fig. S2 (a, b)
Impedance spectra of capacitor filled with 1 mol L1 Li2SO4 aqueous
electrolyte upon 10 and 104 cycles.
Figure S3
F 1s
700000
C 1s
600000
O 1s
500000
Counts
LS
400000
LS+
KOH+
300000
KOH
K 2s
AC
200000
100000
0
0
200
400
600
800
1000
1200
1400
Binding Energy (eV)
Fig. S3
Survey scan of as-prepared AC electrode (AC), and electrode in electrolyte
after 104 cycling. The LS+ and LS denotes the positive and negative electrodes in
Li2SO4, and KOH+ and KOH the ones in KOH, respectively.
Figure S4
(a)
100000
AC
80000
Counts
60000
40000
20000
0
278
280
282
284
286
288
290
292
288
290
292
Binding Energy (eV)
(b)
100000
LS+
Counts
80000
60000
40000
20000
0
278
280
282
284
286
Binding Energy (eV)
(c)
LS
80000
Counts
60000
40000
20000
0
278
280
282
284
286
288
290
292
288
290
292
Binding Energy (eV)
KOH
100000
80000
Counts
60000
40000
20000
0
278
280
282
284
286
Binding Energy (eV)
80000
KOH
Counts
60000
40000
20000
0
278
280
282
284
286
288
290
292
Binding Energy (eV)
Fig. S4
Peak fits of C 1s XPS peaks of positive and negative electrodes in Li2SO4
and KOH, and as-prepared AC electrode, respectively.