BET
Crystal
ΔU versus
Specific
Compound
(m 2 /g)
Structure
Ag/AgCl (V)
Capacitance (F/g)
MnO 2
200
Amorphous
0 to 1
150
Fe 3 O 4
200
Magnetite
–0.7 to 0.2
75
V 2 O 5
Amorphous
–0.2 to 1
170
AC
2800
–1.3 to 0.8
130
170
Electrochemical Supercapacitors for Energy Storage and Delivery
FIGURE 4.21
MnO 2 undergoing cyclic voltammetry analysis in 0.1 M K 2 SO 4 and consecutive redox reactions
that lead to pseudocapacitive charge. Positive current drives reactions between Mn(III) and Mn(IV)
states. (Source: Simon, P. and Y. Gogotsi. 2008. Nature: Materials, 7, 845–854. With permission.)
200 nm
200 nm
(a)
(b)
FIGURE 4.22
SEM images of crystalline MnO 2 materials with interesting (a) belt and (b) urchin morphologies. (Source: Zhang, J. et al. 2011. Nanotechnology, 22, 125703. With permission.)
TABLE 4.3
Performances of Composite Transition Metal Oxide Electrodes Using
K 2 SO 4 Electrolyte Evaluated by CV
Source: Cottineau, T. et al. 2005. Applied Physics A, 82, 599–606. With permission.
Crystal
ΔU versus
Specific
Compound
(m 2 /g)
Structure
Ag/AgCl (V)
Capacitance (F/g)
MnO 2
200
Amorphous
0 to 1
150
Fe 3 O 4
200
Magnetite
–0.7 to 0.2
75
V 2 O 5
Amorphous
–0.2 to 1
170
AC
2800
–1.3 to 0.8
130
170
Electrochemical Supercapacitors for Energy Storage and Delivery
FIGURE 4.21
MnO 2 undergoing cyclic voltammetry analysis in 0.1 M K 2 SO 4 and consecutive redox reactions
that lead to pseudocapacitive charge. Positive current drives reactions between Mn(III) and Mn(IV)
states. (Source: Simon, P. and Y. Gogotsi. 2008. Nature: Materials, 7, 845–854. With permission.)
200 nm
200 nm
(a)
(b)
FIGURE 4.22
SEM images of crystalline MnO 2 materials with interesting (a) belt and (b) urchin morphologies. (Source: Zhang, J. et al. 2011. Nanotechnology, 22, 125703. With permission.)
TABLE 4.3
Performances of Composite Transition Metal Oxide Electrodes Using
K 2 SO 4 Electrolyte Evaluated by CV
Source: Cottineau, T. et al. 2005. Applied Physics A, 82, 599–606. With permission.