10.1002/cplu.201402021
A Microsized Cagelike Sulfur/Carbon Composite for a Lithium/Sulfur Battery with Excellent Performance
Soluble phenolic resin was prepared by following the methods reported by Zhao et al.22 To synthesize MWCNT@mesoporous carbon, the ratio of the carbon source/template/surfactant was optimized, according to Nazar's group.10 In summary, F127 (1.6 g), ethanol (8.0 g), and 0.2 M HCl (1.0 g) were stirred for 2 h at 40 degC to afford a clear solution. Next, TEOS (2.08 g), MWCNTs (1.0 g), and a 20 wt % solution of resols in ethanol were added in sequence and stirred for another 5 h. The mixture was evaporated at room temperature and held for 24 h at 100 degC in an oven for thermo-polymerization. The as-synthesized product was carbonized in a furnace under an argon atmosphere at 900 degC for 300 min. The obtained sample was then washed with 10 wt % HF to remove silica. 
At a weight ratio of 1:1, the MWCNT@MPC composite was mixed with sublimed sulfur under ball-milling for 6 h and then heated at 155 degC for 12 h in an argon atmosphere, resulting in the SC composite. For comparison, pristine S-MPC composite was also prepared by the same method as that described above. For both samples, the sulfur content was 50 wt %.
F127
stirred
1.6 g
g
ethanol
stirred
8.0 g
g
HCl
stirred
0.2 M
M
0.2 M HCl
stirred
1.0 g
g
F127 (1.6 g), ethanol (8.0 g), and 0.2 M HCl
stirred
2 h
h
F127 (1.6 g), ethanol (8.0 g), and 0.2 M HCl
stirred
40 degC
degC
TEOS
added
2.08 g
g
MWCNTs
added
1.0 g
g
solution of resols in ethanol
added
20 wt %
wt %
TEOS (2.08 g), MWCNTs (1.0 g), and a 20 wt % solution of resols in ethanol were added
stirred
5 h
h
mixture
held
24 h
h
mixture
held
100 degC
degC
as-synthesized product
carbonized
900 degC
degC
as-synthesized product
carbonized
300 min
min
HF
10 wt %
wt %
MWCNT@MPC composite was mixed with sublimed sulfur
weight ratio
1:1
MWCNT@MPC composite was mixed with sublimed sulfur
heated
12 h
h
MWCNT@MPC composite was mixed with sublimed sulfur
heated
155 degC
degC
both samples
sulfur content
50 wt %
wt %