3-Dimensional Graphene Carbon Nanotube Carpet-Based Microsupercapacitors with High Electrochemical Performance
711
Citation
29
Reference
10
Related Paper
Citation Trend
Abstract:
In this research, 3-dimensional (3D) graphene/carbon nanotube carpets (G/CNTCs)-based microsupercapacitors (G/CNTCs-MCs) were fabricated in situ on nickel electrodes. The G/CNTCs-MCs show impedance phase angle of -81.5° at a frequency of 120 Hz, comparable to commercial aluminum electrolytic capacitors (AECs) for alternating current (ac) line filtering applications. In addition, G/CNTCs-MCs deliver a high volumetric energy density of 2.42 mWh/cm(3) in the ionic liquid, more than 2 orders of magnitude higher than that of AECs. The ultrahigh rate capability of 400 V/s enables the microdevices to demonstrate a maximum power density of 115 W/cm(3) in aqueous electrolyte. The high-performance electrochemical properties of G/CNTCs-MCs can provide more compact ac filtering units and discrete power sources in future electronic devices. These elevated electrical features are likely enabled by the seamless nanotube/graphene junctions at the interface of the differing carbon allotropic forms.Keywords:
Power density
Carbon fibers
We have successfully fabricated an asymmetric supercapacitor with high energy and power densities using graphene hydrogel (GH) with 3D interconnected pores as the negative electrode and vertically aligned MnO(2) nanoplates on nickel foam (MnO(2)-NF) as the positive electrode in a neutral aqueous Na(2)SO(4) electrolyte. Because of the desirable porous structure, high specific capacitance and rate capability of GH and MnO(2)-NF, complementary potential window of the two electrodes, and the elimination of polymer binders and conducting additives, the asymmetric supercapacitor can be cycled reversibly in a wide potential window of 0-2.0 V and exhibits an energy density of 23.2 Wh kg(-1) with a power density of 1.0 kW kg(-1). Energy density of the asymmetric supercapacitor is significantly improved in comparison with those of symmetric supercapacitors based on GH (5.5 Wh kg(-1)) and MnO(2)-NF (6.7 Wh kg(-1)). Even at a high power density of 10.0 kW kg(-1), the asymmetric supercapacitor can deliver a high energy density of 14.9 Wh kg(-1). The asymmetric supercapacitor also presents stable cycling performance with 83.4% capacitance retention after 5000 cycles.
Power density
Specific energy
Cite
Citations (702)
Co₉S₈/Ni₃S₂ nanoflakes have been successfully designed and constructed on a nickel foam substrate via a simple one-pot hydrothermal synthesis. The as-prepared Co₉S₈/Ni₃S₂ active electrode exhibited superior supercapacitor performance with an area capacitance of 8.95 F cm⁻² at a current density of 6 mA cm⁻², and 7.80 F cm⁻² even at a high power density of 12 mA cm⁻². By applying Co₉S₈/Ni₃S₂ as the positive electrode and porous carbon as the negative electrode, an asymmetric supercapacitor device was fabricated and has shown promising energy densities of 81.7 W h kg⁻¹ at a power density of 0.35 kW kg⁻¹. The stupendous specific capacitance, enhanced cycle stability, elevated energy density and power density as an asymmetric supercapacitor device of these electrode materials indicate that they could be a potential candidate in the field of supercapacitors.
Power density
Hydrothermal Synthesis
Carbon fibers
Cite
Citations (0)
Power density
Energy density
Cite
Citations (30)
Power density
Specific surface area
Energy density
Cite
Citations (74)
Power density
Energy density
Cite
Citations (22)
Supercapacitors with both high energy and high power densities are critical for many practical applications. In this paper, we discuss the design and demonstrate the fabrication of flexible asymmetric supercapacitors based on nanocomposite electrodes of MnO(2), activated carbon, carbon nanotubes and graphene. The combined unique properties of each of these components enable highly flexible and mechanically strong films that can serve as electrodes directly without using any current collectors or binders. Using these flexible electrodes and a roll-up approach, asymmetric supercapacitors with 2 V working voltage were successfully fabricated. The fabricated device showed excellent rate capability, with 78% of the original capacitance retained when the scan rate was increased from 2 mV s(-1) to 500 mV s(-1). Owing to the unique composite structure, these supercapacitors were able to deliver high energy density (24 W h kg(-1)) under high power density (7.8 kW kg(-1)) conditions. These features could enable supercapacitor based energy storage systems to be very attractive for a variety of critical applications, such as the power sources in hybrid electric vehicles and the back-up powers for wind and solar energy, where both high energy density and high power density are required.
Power density
Horizontal scan rate
Cite
Citations (203)
Power density
Carbon fibers
Cite
Citations (19)
Film capacitor
Cite
Citations (0)
Power density
Carbon fibers
Energy density
Cite
Citations (36)
We have investigated the key factors determining the performance of supercapacitors constructed using single-walled carbon nanotube (SWNT) electrodes. Several parameters, such as composition of the binder, annealing temperature, type of current collector, charging time, and discharging current density have been optimized for the best performance of the supercapacitor with respect to energy density and power density. We find a maximum specific capacitance of 180 F/g and a measured power density of 20 kW/kg at energy densities in the range from 7 to 6.5 Wh/kg at 0.9 V in a solution of 7.5 N KOH (the currently available supercapacitors have energy densities in the range 6–7 Wh/kg and power density in the range 0.2–5 kW/kg at 2.3 V in non-aqueous solvents).
Power density
Energy density
Specific energy
Cite
Citations (851)