13-08-2013, 04:55 PM
Ni–NiO core–shell inverse opal electrodes for supercapacitors
[attachment=57140]
ABSTRACT
Electrochemical capacitors (also called supercapacitors and ultra-
capacitors) are emerging energy storage devices because of their
high power density, long cycle life, short charging time, and
minimal safety concerns.1–3 Such devices can be used either by
themselves as a primary power storage source or as an auxiliary
power storage source with rechargeable batteries to meet the
energy needs for high power applications such as electric vehicles
and industrial mobile equipment. Pseudo-capacitors (or redox-
capacitors) represent one type of supercapacitors that have the
potential to achieve high energy densities resulting from the fast
and reversible redox reactions at/near the interface of the active
storage material and an electrolyte. Among various pseudo-
capacitor materials, hydrous RuO2 exhibits the highest perfor-
mance to date,4,5 but its high cost limits its commercial use.
Therefore, there has been considerable effort in exploring alter-
native electrode materials showing pseudo-capacitive behaviors,
such as manganese oxide,6,7 cobalt oxide,8 and nickel oxide.9–
For high-power applications, adequate power density is only
achieved with fast electron and ion transport. Conventional
nanostructured electrode materials usually consist of a disordered
porous matrix (e.g., sintered nanoparticle film); these electrode
materials exhibit poor electrical and mechanical contact and an
ill-defined pore network that impedes electronic and ionic
conductions during charge/discharge cycling. This study addresses
these challenges simultaneously with a structural motif that has
not been applied to supercapacitors: a metal core–metal oxide
shell inverse opal (IO) electrode.
[attachment=57140]
ABSTRACT
Electrochemical capacitors (also called supercapacitors and ultra-
capacitors) are emerging energy storage devices because of their
high power density, long cycle life, short charging time, and
minimal safety concerns.1–3 Such devices can be used either by
themselves as a primary power storage source or as an auxiliary
power storage source with rechargeable batteries to meet the
energy needs for high power applications such as electric vehicles
and industrial mobile equipment. Pseudo-capacitors (or redox-
capacitors) represent one type of supercapacitors that have the
potential to achieve high energy densities resulting from the fast
and reversible redox reactions at/near the interface of the active
storage material and an electrolyte. Among various pseudo-
capacitor materials, hydrous RuO2 exhibits the highest perfor-
mance to date,4,5 but its high cost limits its commercial use.
Therefore, there has been considerable effort in exploring alter-
native electrode materials showing pseudo-capacitive behaviors,
such as manganese oxide,6,7 cobalt oxide,8 and nickel oxide.9–
For high-power applications, adequate power density is only
achieved with fast electron and ion transport. Conventional
nanostructured electrode materials usually consist of a disordered
porous matrix (e.g., sintered nanoparticle film); these electrode
materials exhibit poor electrical and mechanical contact and an
ill-defined pore network that impedes electronic and ionic
conductions during charge/discharge cycling. This study addresses
these challenges simultaneously with a structural motif that has
not been applied to supercapacitors: a metal core–metal oxide
shell inverse opal (IO) electrode.