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Paul K Chu - One of the best experts on this subject based on the ideXlab platform.

  • field emission from geometrically modulated tungsten nickel sulfide graphitic carbon nanobelts on si Microchannel Plates
    Ceramics International, 2020
    Co-Authors: Yuyao Che, Lianwei Wang, Xueku Hong, Wei Ouyang, Shi Tao, Quanliang Zhao, I Qia, Paul K Chu
    Abstract:

    Abstract The low efficiency and instability of electron emission from two-dimensional (2D) materials such as WS2 and NiS hamper application to vacuum microelectronic devices. Although nickel-based alloys have many favorable physicochemical properties suitable for nanoelectronics, electron field emission (FE) from heterostructures comprising tungsten-nickel sulfide alloys and graphite carbon (WNi–S/C) has been seldom studied because it is difficult to fabricate the nanostructures in situ. In this work, field emitters composed of the WNi–S/C nanobelt composite are produced on Si Microchannel Plates (WNi–S/C@Si) hydrothermally. The structure has a porous and vertically aligned 3D morphology in addition to excellent adhesion strength with the substrate. Geometrical modulation of the WNi–S/C@Si is performed by changing the hydrothermal reaction temperature and an ultralow turn-on electric field of 0.51 V μm−1 for a current density 0.1 mA cm−2, threshold electric field of 0.65 V μm−1 for a current density of 1 mA cm−2, and stability of 97.1% for 8 h are accomplished. The related mechanisms are investigated and discussed. Moreover, finite element simulation shows that not only the shape of the nanostructures but also the high aspect plays a key role in reducing screen effects. These outstanding properties suggest large potential in high-performance FE and vacuum nanodevices.

  • manganese molybdate nanoflakes on silicon Microchannel Plates as novel nano energetic material
    Royal Society Open Science, 2017
    Co-Authors: Chi Zhang, Lianwei Wang, Liming Shi, Yiping Zhu, Dayua Xiong, Rong Huang, Wenchao Zhang, Paul K Chu
    Abstract:

    Nano energetic materials have attracted great attention recently owing to their potential applications for both civilian and military purposes. By introducing silicon Microchannel Plates (Si-MCPs) ...

  • vertically oriented few layer graphene supported by silicon Microchannel Plates as a counter electrode in dye sensitized solar cells
    Organic Electronics, 2017
    Co-Authors: Fengjua Miao, Paul K Chu, Airui Tao, Rui Miao, Fang Liu, Lili Shao, Xiaodong Zhu
    Abstract:

    Abstract Vertically-oriented few-layer graphene supported by silicon Microchannel Plates annealed at different temperatures are used in dye-sensitized solar cells (DSSCs). The structure, morphology, and electrochemical characteristics are determined by AFM, SEM, XPS, cyclic voltammetry, electrochemical impedance spectroscopy, and photocurrent density-voltage curves. The graphene/Si-MCP fabricated by electrochemical exfoliation delivers enhanced power conversion efficiency in DSSC and the materials annealed under ambient conditions at 300 °C show the best results due to the smaller oxygen concentration in graphene and larger electrical conductance. Owing to the microelectronics-compatible fabrication process and excellent properties of the device, the counter electrode has large potential in high-performance silicon-based monolithic DSSCs.

  • preparation of multi layer graphene on nickel coated silicon Microchannel Plates by a hydrothermal carbonization procedure and its improved field emission properties
    Journal of Materials Chemistry C, 2016
    Co-Authors: Chi Zhang, Lianwei Wang, Yiping Zhu, Dayua Xiong, Cheng Liang, Shaoli Xue, Paul K Chu
    Abstract:

    An emission cell comprising multi-layer graphene (MLG) on nickel-coated silicon Microchannel Plates (Ni/Si-MCPs) was prepared. The Ni3C film was formed on the Si-MCPs by hydrothermal carburization in a polyol solution containing a small amount of NaAc as the carbon source and thermal annealing was performed to produce the vertically and horizontally aligned multi-layer graphene field-emission cathode on the surface of the Ni/Si-MCPs (MLG-MCPs). The microstructure and surface morphology were investigated and field emission (FE) studies indicated that the MLG-MCPs delivered better FE performance than Ni/Si-MCPs due to characteristics such as sharp edges, large aspect ratio, and the vertically and horizontally aligned and patterned MLG with good electrical conductivity. The turn-on field of the sample annealed at 800 °C was 2.0 V μm−1 at a current density of 10 μA cm−2 and the field emission threshold was 3.2 V μm−1 at 1 mA cm−2. The structure was very stable showing 97.5% retention after continuous operation for over 6 h at 2 × 10−5 Pa, suggesting a promising candidate for FE devices. This would open up possibilities for the next generation FE electron sources from well-aligned macroporous graphene with skeleton and extend their practical applications.

  • electrochemical investigation of the corrosion properties of three dimensional nickel electrodes on silicon Microchannel Plates
    Corrosion Science, 2015
    Co-Authors: Yiping Zhu, Lianwei Wang, Dayua Xiong, Wenchao Zhang, Pingxiong Yang, Paul K Chu
    Abstract:

    Abstract The corrosion properties of three-dimensional nickel electrodes deposited on silicon Microchannel Plates by electroless and electrodeposition processes are studied by electrochemical methods. The nickel thin film deposited on the silicon Microchannel plate protects the silicon skeleton in the aqueous electrolytes containing alkalis and salts and the electrolyte containing salts may be a good choice due to the low corrosion rate and no damage to silicon. The nickel-coated silicon Microchannel plate electrodes exhibit low resistance and high surface defect concentration after the electrodeposition process and p- and n-type semiconductor properties are observed in the alkali and salt media, respectively.

Lianwei Wang - One of the best experts on this subject based on the ideXlab platform.

  • field emission from geometrically modulated tungsten nickel sulfide graphitic carbon nanobelts on si Microchannel Plates
    Ceramics International, 2020
    Co-Authors: Yuyao Che, Lianwei Wang, Xueku Hong, Wei Ouyang, Shi Tao, Quanliang Zhao, I Qia, Paul K Chu
    Abstract:

    Abstract The low efficiency and instability of electron emission from two-dimensional (2D) materials such as WS2 and NiS hamper application to vacuum microelectronic devices. Although nickel-based alloys have many favorable physicochemical properties suitable for nanoelectronics, electron field emission (FE) from heterostructures comprising tungsten-nickel sulfide alloys and graphite carbon (WNi–S/C) has been seldom studied because it is difficult to fabricate the nanostructures in situ. In this work, field emitters composed of the WNi–S/C nanobelt composite are produced on Si Microchannel Plates (WNi–S/C@Si) hydrothermally. The structure has a porous and vertically aligned 3D morphology in addition to excellent adhesion strength with the substrate. Geometrical modulation of the WNi–S/C@Si is performed by changing the hydrothermal reaction temperature and an ultralow turn-on electric field of 0.51 V μm−1 for a current density 0.1 mA cm−2, threshold electric field of 0.65 V μm−1 for a current density of 1 mA cm−2, and stability of 97.1% for 8 h are accomplished. The related mechanisms are investigated and discussed. Moreover, finite element simulation shows that not only the shape of the nanostructures but also the high aspect plays a key role in reducing screen effects. These outstanding properties suggest large potential in high-performance FE and vacuum nanodevices.

  • manganese molybdate nanoflakes on silicon Microchannel Plates as novel nano energetic material
    Royal Society Open Science, 2017
    Co-Authors: Chi Zhang, Lianwei Wang, Liming Shi, Yiping Zhu, Dayua Xiong, Rong Huang, Wenchao Zhang, Paul K Chu
    Abstract:

    Nano energetic materials have attracted great attention recently owing to their potential applications for both civilian and military purposes. By introducing silicon Microchannel Plates (Si-MCPs) ...

  • preparation of multi layer graphene on nickel coated silicon Microchannel Plates by a hydrothermal carbonization procedure and its improved field emission properties
    Journal of Materials Chemistry C, 2016
    Co-Authors: Chi Zhang, Lianwei Wang, Yiping Zhu, Dayua Xiong, Cheng Liang, Shaoli Xue, Paul K Chu
    Abstract:

    An emission cell comprising multi-layer graphene (MLG) on nickel-coated silicon Microchannel Plates (Ni/Si-MCPs) was prepared. The Ni3C film was formed on the Si-MCPs by hydrothermal carburization in a polyol solution containing a small amount of NaAc as the carbon source and thermal annealing was performed to produce the vertically and horizontally aligned multi-layer graphene field-emission cathode on the surface of the Ni/Si-MCPs (MLG-MCPs). The microstructure and surface morphology were investigated and field emission (FE) studies indicated that the MLG-MCPs delivered better FE performance than Ni/Si-MCPs due to characteristics such as sharp edges, large aspect ratio, and the vertically and horizontally aligned and patterned MLG with good electrical conductivity. The turn-on field of the sample annealed at 800 °C was 2.0 V μm−1 at a current density of 10 μA cm−2 and the field emission threshold was 3.2 V μm−1 at 1 mA cm−2. The structure was very stable showing 97.5% retention after continuous operation for over 6 h at 2 × 10−5 Pa, suggesting a promising candidate for FE devices. This would open up possibilities for the next generation FE electron sources from well-aligned macroporous graphene with skeleton and extend their practical applications.

  • electrochemical investigation of the corrosion properties of three dimensional nickel electrodes on silicon Microchannel Plates
    Corrosion Science, 2015
    Co-Authors: Yiping Zhu, Lianwei Wang, Dayua Xiong, Wenchao Zhang, Pingxiong Yang, Paul K Chu
    Abstract:

    Abstract The corrosion properties of three-dimensional nickel electrodes deposited on silicon Microchannel Plates by electroless and electrodeposition processes are studied by electrochemical methods. The nickel thin film deposited on the silicon Microchannel plate protects the silicon skeleton in the aqueous electrolytes containing alkalis and salts and the electrolyte containing salts may be a good choice due to the low corrosion rate and no damage to silicon. The nickel-coated silicon Microchannel plate electrodes exhibit low resistance and high surface defect concentration after the electrodeposition process and p- and n-type semiconductor properties are observed in the alkali and salt media, respectively.

  • electronic double layer supercapacitor based on three dimensional silicon Microchannel Plates in organic electrolyte
    Materials Research Innovations, 2015
    Co-Authors: Yiping Zhu, Lianwei Wang, L J Zhou, Paul K Chu
    Abstract:

    Spurred by the fast development and commercial appeal of the energy storage device, supercapacitor with large capacity and wide potential range is being more and more popular. An electronic double layer supercapacitor consisting of three-dimensional silicon Microchannel Plates and electroplated MnO2 nanoflakes as the active materials of the positive electrode is fabricated and evaluated systematically in an organic electrolyte (1M LiClO4 in propylene carbonate). Its composition, morphology, electrochemical impedance and charge storage mechanism are studied and compared to that of a planar structure. The silicon Microchannel Plates increase the specific area for loading of active materials. This supercapacitor with a large aspect ratio delivers excellent capacitive performance in limited space and weight. A single device made of the materials can power light emitting diodes, demonstrating its commercial potential.

Yiping Zhu - One of the best experts on this subject based on the ideXlab platform.

  • manganese molybdate nanoflakes on silicon Microchannel Plates as novel nano energetic material
    Royal Society Open Science, 2017
    Co-Authors: Chi Zhang, Lianwei Wang, Liming Shi, Yiping Zhu, Dayua Xiong, Rong Huang, Wenchao Zhang, Paul K Chu
    Abstract:

    Nano energetic materials have attracted great attention recently owing to their potential applications for both civilian and military purposes. By introducing silicon Microchannel Plates (Si-MCPs) ...

  • preparation of multi layer graphene on nickel coated silicon Microchannel Plates by a hydrothermal carbonization procedure and its improved field emission properties
    Journal of Materials Chemistry C, 2016
    Co-Authors: Chi Zhang, Lianwei Wang, Yiping Zhu, Dayua Xiong, Cheng Liang, Shaoli Xue, Paul K Chu
    Abstract:

    An emission cell comprising multi-layer graphene (MLG) on nickel-coated silicon Microchannel Plates (Ni/Si-MCPs) was prepared. The Ni3C film was formed on the Si-MCPs by hydrothermal carburization in a polyol solution containing a small amount of NaAc as the carbon source and thermal annealing was performed to produce the vertically and horizontally aligned multi-layer graphene field-emission cathode on the surface of the Ni/Si-MCPs (MLG-MCPs). The microstructure and surface morphology were investigated and field emission (FE) studies indicated that the MLG-MCPs delivered better FE performance than Ni/Si-MCPs due to characteristics such as sharp edges, large aspect ratio, and the vertically and horizontally aligned and patterned MLG with good electrical conductivity. The turn-on field of the sample annealed at 800 °C was 2.0 V μm−1 at a current density of 10 μA cm−2 and the field emission threshold was 3.2 V μm−1 at 1 mA cm−2. The structure was very stable showing 97.5% retention after continuous operation for over 6 h at 2 × 10−5 Pa, suggesting a promising candidate for FE devices. This would open up possibilities for the next generation FE electron sources from well-aligned macroporous graphene with skeleton and extend their practical applications.

  • electrochemical investigation of the corrosion properties of three dimensional nickel electrodes on silicon Microchannel Plates
    Corrosion Science, 2015
    Co-Authors: Yiping Zhu, Lianwei Wang, Dayua Xiong, Wenchao Zhang, Pingxiong Yang, Paul K Chu
    Abstract:

    Abstract The corrosion properties of three-dimensional nickel electrodes deposited on silicon Microchannel Plates by electroless and electrodeposition processes are studied by electrochemical methods. The nickel thin film deposited on the silicon Microchannel plate protects the silicon skeleton in the aqueous electrolytes containing alkalis and salts and the electrolyte containing salts may be a good choice due to the low corrosion rate and no damage to silicon. The nickel-coated silicon Microchannel plate electrodes exhibit low resistance and high surface defect concentration after the electrodeposition process and p- and n-type semiconductor properties are observed in the alkali and salt media, respectively.

  • electronic double layer supercapacitor based on three dimensional silicon Microchannel Plates in organic electrolyte
    Materials Research Innovations, 2015
    Co-Authors: Yiping Zhu, Lianwei Wang, L J Zhou, Paul K Chu
    Abstract:

    Spurred by the fast development and commercial appeal of the energy storage device, supercapacitor with large capacity and wide potential range is being more and more popular. An electronic double layer supercapacitor consisting of three-dimensional silicon Microchannel Plates and electroplated MnO2 nanoflakes as the active materials of the positive electrode is fabricated and evaluated systematically in an organic electrolyte (1M LiClO4 in propylene carbonate). Its composition, morphology, electrochemical impedance and charge storage mechanism are studied and compared to that of a planar structure. The silicon Microchannel Plates increase the specific area for loading of active materials. This supercapacitor with a large aspect ratio delivers excellent capacitive performance in limited space and weight. A single device made of the materials can power light emitting diodes, demonstrating its commercial potential.

  • asymmetrical supercapacitor composed of thin co oh 2 nanoflakes on three dimensional ni si Microchannel Plates with superior electrochemical performance
    Electrochimica Acta, 2014
    Co-Authors: Lianwei Wang, Yiping Zhu, Rong Huang, Pingxiong Yang, Christophe Cherry, Paul K Chu
    Abstract:

    Abstract Nanoscale cobalt hydroxide (Co(OH)2) particles are fabricated by electrodeposition on three-dimensional nickel/silicon Microchannel Plates (Ni/Si-MCPs) as the active electrode materials on the surface and sidewall of the Ni/Si-MCPs for miniature supercapacitors. The relationship among the electrodeposition time, morphology, formation mechanism of Co(OH)2 nanostructure, and capacitor performance is studied. Using an optimal electrodeposition time of 6 min, the Co(OH)2 supercapacitor has a capacitance of 697.56 F g−1 (5.72 F cm−2) at 2 mA cm−2 and the retention ratio is 91.20% after 2500 cycles. The large areal capacitance and excellent rate capability can be attributed to the unique 3D ordered porous architecture which facilitates electron and ion transport, enlarges the liquid-solid interfacial area, and enhances the utilization efficiency of the active materials. Meanwhile, the weight and size of the device are reduced. By using the Co(OH)2/Ni/Si-MCPs electrode as the positive electrode and CNTs/nickel foam (CNTs/NF) as the negative electrode, the device assembled with CR2025 batteries exhibits high energy density (38.39 Wh kg−1), high power density (5400 W kg−1 at 9.67 Wh kg−1), and stable power characteristic (2000 times with 80.63% retention). After charging each supercapacitor for 10 s, the device can power a 5 mm diameter light-emitting diode (LED) with different colors efficiently, for example, a blue LED for 20 min.

A S Tremsi - One of the best experts on this subject based on the ideXlab platform.

  • overview of spatial and timing resolution of event counting detectors with Microchannel Plates
    Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2020
    Co-Authors: A S Tremsi, J V Vallerga, O H W Siegmund
    Abstract:

    Abstract Event counting detectors with Microchannel Plates (MCPs) rely on conversion of incoming particles (photons, electrons, neutrons, atoms, ions) into an output charge of 103–107 electrons. This signal multiplication enables operation of those detectors at virtually zero readout noise and at very low input fluxes. The encoding of event position and timing can be performed by various types of readout configurations, which need to be selected for a particular experiment. Substantial developments in microelectronics have extended the capabilities of MCP counting detectors to GHz rates, increased their formats to 20 cm and allowed detection of multiple simultaneous events with spatial and timing resolution as good as ∼ 10 μ m and ∼ 10–20 ps, respectively. Unfortunately not all these characteristics are available in a single device. A brief overview of performance characteristics of event counting MCP detectors with different readouts is presented in this paper, providing the guidance for the selection of a particular detector configuration for a given set of experimental requirements.

  • optimization of spatial resolution and detection efficiency for photon electron neutron ion counting detectors with Microchannel Plates and quad timepix readout
    Journal of Instrumentation, 2018
    Co-Authors: A S Tremsi, J V Vallerga, R Raffanti
    Abstract:

    Although event counting detectors with Microchannel Plates (MCPs) were originally developed primarily for applications with low input fluxes, recent progress in readout electronics substantially extended their counting rate capabilities, while still maintaining very low dark count rates and no readout noise. Detection of many simultaneous events and operation at rates exceeding 100 MHz has been demonstrated with combination of MCPs and a Timepix readout. The spatial resolution in such devices can be an order of magnitude better than the 55 μm pixel size of Timepix chips when event centroiding is implemented. However, a compromise between spatial resolution and the number of accepted events has to be found for such detectors operating at high rates. Here we present an MCP/Timepix detector capable of simultaneous detection of an image with the highest spatial resolution of ~6.5 μm, but reduced number of counts and an image with all registered photons but reduced 55 μm spatial resolution. A compromise between detector resolution and the acquisition duty cycle is also discussed. It was confirmed that high spatial resolution can still be maintained through event centroiding even with 60% of pixels hit by more than one photon per acquisition frame.

  • development of opaque photocathodes deposited onto Microchannel Plates
    Nuclear Science Symposium and Medical Imaging Conference, 2017
    Co-Authors: Camde Ertley, A S Tremsi, O H W Siegmund, J Elam, J. Hull, J Tedesco, A M Dabira, Anil U Mane
    Abstract:

    Atomic layer deposition (ALD) techniques are being used to manufacture Microchannel plate (MCP) imaging electron multipliers. The MCP substrates are borosilicate microcapillary arrays, which are more robust than traditional lead glass MCPs, allowing them to be produced in large formats (400 cm2) with high open area ratios (up to 85%). The application of resistive and secondary emissive layers using ALD allow custom nanofabrication and optimization of parameters such as gain and resistance. The UV quantum efficiency of bare ALD MCPs exceeds conventional MCPs and application of opaque alkali halide photocathode layers have been investigated. The robust nature of ALD MCPs means they can also withstand the processing temperatures required for high temperature deposition of III-V materials, such as Gallium Nitride (GaN), for UV photocathodes with high QEs in the Near-UV $(\sim 200-300$nm). Here we discuss the status of the QE of bare ALD MCPs and the results of our opaque photocathode deposition effort onto ALD MCPs. Initial trials of opaque bialkali depositions have been successfully completed showing detection efficiencies commensurate with the highest efficiency semitransparent cathodes. GaN has been grown by molecular beam epitaxy onto sapphire substrates in order to optimize the deposition parameters. These results are being used as a diagnostic for refining depositions of GaN directly onto ALD MCPs.

  • application of atomic layer deposited Microchannel Plates to imaging photodetectors with high time resolution
    Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2015
    Co-Authors: O H W Siegmund, N Richne, J Mcphate, A S Tremsi, Henry J Frisch, Jeffrey W Elam, J V Vallerga, Camde Ertley, Thomas Gerard, Anil U Mane
    Abstract:

    Abstract Novel Microchannel Plates have been constructed using borosilicate glass micro-capillary array substrates with 20 µm and 10 µm pores and coated with resistive, and secondary electron emissive, layers by atomic layer deposition. Microchannel Plates in 33 mm, 50 mm and 20 cm square formats have been made and tested. Although their amplification, imaging, and timing properties are comparable to standard glass Microchannel Plates, the background rates and lifetime characteristics are considerably improved. Sealed tube detectors based on the Planacon tube, and a 25 mm cross delay line readout tube with a GaN(Mg) opaque photocathode deposited on borosilicate Microchannel Plates have been fabricated. Considerable progress has also been made with 20 cm Microchannel Plates for a 20 cm format sealed tube sensor with strip-line readout that is being developed for Cherenkov light detection.

  • performance characteristics of atomic layer functionalized Microchannel Plates
    Proceedings of SPIE, 2013
    Co-Authors: O H W Siegmund, N Richne, Gautam Gunjala, J Mcphate, A S Tremsi, Henry J Frisch, Jeffrey W Elam, Anil U Mane, R G Wagne, Christophe A Crave
    Abstract:

    Microchannel Plates that have been constructed by atomic layer deposition of resistive and secondary emissive layers, onto borosilicate glass microcapillary arrays provide a novel alternative to conventional Microchannel Plates for detection of radiation and particles. Conventional Microchannel Plates can also benefit from atomic layer deposition of highly efficient secondary emissive layers. Our evaluations of these techniques have revealed unique features of atomic layer functionalized Microchannel Plates, including enhanced stability and lifetime, low background rates, and low levels of adsorbed gas. In addition borosilicate glass microcapillary arrays show enhanced physical and thermal robustness, which makes it possible to successfully fabricate large area devices (20 cm) with good uniformity of operational characteristics.

Pingxiong Yang - One of the best experts on this subject based on the ideXlab platform.

  • electrochemical investigation of the corrosion properties of three dimensional nickel electrodes on silicon Microchannel Plates
    Corrosion Science, 2015
    Co-Authors: Yiping Zhu, Lianwei Wang, Dayua Xiong, Wenchao Zhang, Pingxiong Yang, Paul K Chu
    Abstract:

    Abstract The corrosion properties of three-dimensional nickel electrodes deposited on silicon Microchannel Plates by electroless and electrodeposition processes are studied by electrochemical methods. The nickel thin film deposited on the silicon Microchannel plate protects the silicon skeleton in the aqueous electrolytes containing alkalis and salts and the electrolyte containing salts may be a good choice due to the low corrosion rate and no damage to silicon. The nickel-coated silicon Microchannel plate electrodes exhibit low resistance and high surface defect concentration after the electrodeposition process and p- and n-type semiconductor properties are observed in the alkali and salt media, respectively.

  • asymmetrical supercapacitor composed of thin co oh 2 nanoflakes on three dimensional ni si Microchannel Plates with superior electrochemical performance
    Electrochimica Acta, 2014
    Co-Authors: Lianwei Wang, Yiping Zhu, Rong Huang, Pingxiong Yang, Christophe Cherry, Paul K Chu
    Abstract:

    Abstract Nanoscale cobalt hydroxide (Co(OH)2) particles are fabricated by electrodeposition on three-dimensional nickel/silicon Microchannel Plates (Ni/Si-MCPs) as the active electrode materials on the surface and sidewall of the Ni/Si-MCPs for miniature supercapacitors. The relationship among the electrodeposition time, morphology, formation mechanism of Co(OH)2 nanostructure, and capacitor performance is studied. Using an optimal electrodeposition time of 6 min, the Co(OH)2 supercapacitor has a capacitance of 697.56 F g−1 (5.72 F cm−2) at 2 mA cm−2 and the retention ratio is 91.20% after 2500 cycles. The large areal capacitance and excellent rate capability can be attributed to the unique 3D ordered porous architecture which facilitates electron and ion transport, enlarges the liquid-solid interfacial area, and enhances the utilization efficiency of the active materials. Meanwhile, the weight and size of the device are reduced. By using the Co(OH)2/Ni/Si-MCPs electrode as the positive electrode and CNTs/nickel foam (CNTs/NF) as the negative electrode, the device assembled with CR2025 batteries exhibits high energy density (38.39 Wh kg−1), high power density (5400 W kg−1 at 9.67 Wh kg−1), and stable power characteristic (2000 times with 80.63% retention). After charging each supercapacitor for 10 s, the device can power a 5 mm diameter light-emitting diode (LED) with different colors efficiently, for example, a blue LED for 20 min.

  • three dimensional nanoscale co3o4 electrode on ordered ni si Microchannel Plates for electrochemical supercapacitors
    Materials Letters, 2014
    Co-Authors: Yiping Zhu, Lianwei Wang, Pingxiong Yang, Paul K Chu
    Abstract:

    Abstract Nanoscale cobalt oxide (Co 3 O 4 ) particles are produced on three-dimensional nickel/silicon Microchannel Plates (Ni/Si-MCPs) as the active electrode materials in miniature supercapacitors. The Co 3 O 4 nano-flakes are fabricated on the surface and interior of the Ni/Si-MCPs by annealing the nano-structured Co(OH) 2 /Ni/Si-MCPs, and the electrical conductivity and capacitance retention are improved. The Ni/Si-MCPs covered with nano-flaked Co 3 O 4 supercapacitor offer smaller charging current leakage and higher discharging voltage than Ni/Si-MCPs electrodeposited with cobalt hydroxide {Co(OH) 2 }. Specific capacitance as high as 2.424 F/cm 2 or 606.24 F/g is achieved from the materials and the retention ratio is 89.85% after 2000 cycles thus demonstrating excellent potential in miniature supercapacitors.

  • heterostructured ni oh 2 co oh 2 composites on 3d ordered ni co nanoparticles fabricated on Microchannel Plates for advanced miniature supercapacitor
    Journal of Alloys and Compounds, 2014
    Co-Authors: Yiping Zhu, Lianwei Wang, Pingxiong Yang, Paul K Chu
    Abstract:

    Abstract Silicon Microchannel Plates (Si-MCPs) coated with a layer of nickel cobalt alloy (NCA) constitute an excellent substrate for miniature supercapacitors. Nanoscale Ni(OH)2–Co(OH)2 composite particles serving as the active materials are electrodeposited on ordered three-dimensional (3D) NCA/Ni/Si-MCPs and the Ni(OH)2–Co(OH)2 composites have different structures depending on the amount of Co(OH)2 in Ni(OH)2. The nickel hydroxide synthesized from a water–acetone 0.1 M Ni(NO3)2⋅6H2O solvent has a compact structure, but that from a 0.1 M Ni(NO3)2⋅6H2O solvent containing 5% Co(NO3)2⋅6H2O is loosely packed with nanoparticles and that from a 0.1 M Ni(NO3)2⋅6H2O solvent containing 10% Co(NO3)2⋅6H2O contains many nanoparticles. Addition of Co(NO3)2⋅6H2O results in a smooth morphology. The smooth structure is also observed from active materials produced in 20% and 30% Co(NO3)2⋅6H2O solvents. Five types of electrode materials are investigated from the perspective of electrochemical capacitors by conducting cyclic voltammogram, galvanostatic charge–discharge measurements, and electrochemical impedance spectroscopy. In this experiment, the highest specific capacitance of 7.8 F cm−2 is achieved in the samples prepared in 10% Co(NO3)2⋅6H2O at a discharge current density of 20 mA cm−2. It is much better than 1.46 F cm−2 observed from previous attempts and the materials have excellent capacity retention.

  • anode properties and morphology evolution of three dimensional lithium ion battery electrodes comprising ni coated si Microchannel Plates
    Journal of Alloys and Compounds, 2013
    Co-Authors: Fei Wang, Lianwei Wang, Keshuang Hui, Pingxiong Yang, Shansha Zhu, Xuefeng Lou, Yiwei Che, Paul K Chu
    Abstract:

    Abstract Using lithium foils as the counter electrodes and Ni-coated Si Microchannel Plates (Si-MCPs) as the matrix and active materials, half-cells were fabricated and tested. Galvanostatic charge–discharge (C–D) measurements were conducted at 100 mA g −1 between 0.05 and 1.5 V. By decreasing the Li insertion/extraction level, the Ni/Si-MCP anode retained the reversible discharge capacity of 1000 mA h g −1 for 80 cycles and 500 mA h g −1 for 104 cycles, respectively. The morphology of the Ni/Si-MCP after the galvanostatic cycles was examined by scanning electron microscope (SEM). Based on the results of electrochemical impedance spectroscopy (EIS) and energy-dispersive X-ray spectroscopy (EDS), the mechanism of electrode fading was investigated and described.