We have synthesized the hybrid supercapacitor electrode of Co3O4 nanoparticles on vertically aligned graphene nanosheets (VAGNs) supported by carbon fabric. The VAGN served as an excellent backbone together with the carbon fabric, enhancing composites to a high specific capacitance of 3480 F/g, approaching the theoretical value (3560 F/g). A highly flexible all-solid-state symmetric supercapacitor device was fabricated by two pieces of our Co3O4/VAGN/carbon fabric hybrid electrode. The device is suitable for different bending angles and delivers a high capacitance (580 F/g), good cycling ability (86.2% capacitance retention after 20 000 cycles), high energy density (80 Wh/kg), and high power density (20 kW/kg at 27 Wh/kg). These excellent electrochemical performances, as a result of the particular structure of VAGN and the flexibility of the carbon fabric, suggest that these composites have an enormous potential in energy application.
New layered SnS2 nanosheet arrays consisting
of 1–5
atomic layers were synthesized directly on Sn foil as both the tin
source and the metal current collector substrates by a simple biomolecule-assisted
method. It is found that SnS2 nanosheets synthesized have
excellent photoelectric applications, such as on lithium ion batteries,
and photocatalytic, field emission, and photoconductive properties.
Cyclic voltammetry and discharge and charge behaviors of the atomic
SnS2 nanosheets were examined, and it shows that the average
discharge capacity in 1050 mAh/g is much larger than the theoretical
capacity at the 1C rate. The photocatalytic action driven by solar
light is quite quick, and the degradation rate of RhB is 90%, only
irradiated for 20 min when the content of SnS2 nanosheets
is 0.4 g/L. The response of the SnS2 device to the incidence
UV light is very fast and shows excellent photosensitivity and stability.
In addition, field emission properties of SnS2 nanosheets
were also researched, and we found that the turn-on field for SnS2 is 6.9 V/μm, which lowered ever reported values. The
enhanced photoelectric properties are likely to originate in a graphene-like
structure. Thus, graphene-like SnS2 materials are promising
candidates in the photoelectric field.
Highly efficient energy storage systems are in great demand for power source applications ranging from wearable electronics to hybrid electric vehicles. Graphene-based hybrid structure capacitors are ideal candidates for manufacturing these systems. Herein, we present the design and fabrication of heterostructured composites made of vertically aligned graphene nanosheets (VAGN) and MnO nanoparticles. Electrodes with various MnO mass contents were obtained by depositing nanosized MnO particles onto VAGN under different hydrothermal conditions. The VAGN served as an excellent backbone and electron collector, enhancing the specific capacitance of the VAGN/MnO electrode (37 wt% MnO) to 790 F g À1 at a scan rate of 2 mV s À1 . The electrodes also showed high specific capacitance (381 F g À1 ) with high active material loading content (80 wt% MnO), and outstanding cycling stability (80% retention after 4000 cycles at 10 A g À1 ). These excellent electrochemical performances result from the particular three-dimensional structure of VAGN, which offers convenient access for electrolyte cations participating in the redox reaction of MnO. These composites show enormous potential for use in energy management applications.
A 3D-composite structure of FeP nanorods on vertically aligned graphene nanosheets has been fabricated for the high-performance hydrogen evolution reaction.
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